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NAME
pppd - 點對點協議守護程序
總覽 SYNOPSIS
pppd [ tty_name ] [ speed ] [ options ]
描述
點對點協議 (PPP) 提供一種在點對點串列線路上傳輸資料流 (datagrams)的方法。PPP是由三個部份所
組成的：一個在串列線 路上封裝(encapsulating)資料流的方法，一個可延伸的連結控制 協
定(LinkControlProtocol:LCP)，以及一些用來建立並配置不 同網路層協定的網路控制協
定(NetworkControlProtocols:NCP)
封裝的機制(scheme)是由核心中的驅動程式碼來提供。pppd提供 基本的LCP，驗證(authentication)的
支援，以及一個用來建立 並配置網際網路協定(InternatProtocol(IP))（叫做IP控制 協
定，IPCP）的NCP。
常用選項 FREQUENTLY USED OPTIONS
<tty_name>
在該名稱的裝置上進行通訊。如果需要的話可以前置一個 "/dev/"字串。如果沒有給裝置名
稱，pppd將會使用控制 臺的終端機(controllingteriminal)，並且產生(fork)出 來時將不會
把自己放到背景去。
<speed>
將波特率設為speed。在像是4.4BSD以及NetBSA的系 統上，可以指定任何速率。其他系
統(e.g.SunOs)只允 許有限的幾種速率。
asyncmap <map>
把非同步(async)字元設為對照到。這個對照表 描述哪些控制字元不能在串列線路上成功地接
收。pppd將 會要求彼端以兩個位元組的逸出序列(escapesequence)來 傳送這些字元。其引數
是32位元的十六進位數字而每個 位元代表一個得避開(escape)的字元。位元0(00000001) 代表
字元0x00；位元31(80000000)代表字元0x1f或 是^_。如果給了多個asyncmap選項，這些數值會
以邏 輯的或(OR)合在一起。如果沒有給asyncmap選項，將沒 有非同步字元對照表會被加以協
商來導引接收。這樣彼端 將會避開所有的控制字元。
auth 要求彼端在允許傳送或接收網路封包之前先驗證它自己。 This option is the default if
the system has a default route. If neither this option nor the noauth option is
specified, pppd will only allow the peer to use IP addresses to which the system
does not already have a route.
call name
Read options from the file /etc/ppp/peers/name. This file may contain privileged
options, such as noauth, even if pppd is not being run by root. The name string
may not begin with / or include .. as a pathname component. The format of the
options file is described below.
connect script
使用以所指定的可執行指令或是shell指令來設定 串列線路。這個指令稿一般會使用"chat"程
式來撥資料 機並開始遠端ppp區段作業(session)。 A value for this option from a
privileged source cannot be overridden by a non-privileged user.
crtscts
使用硬體流量控制(i.e.RTS/CTS)來控制串列埠上的資料流。 If neither the crtscts, the
nocrtscts, the cdtrcts nor the nocdtrcts option is given, the hardware flow control
setting for the serial port is left unchanged. Some serial ports (such as
Macintosh serial ports) lack a true RTS output. Such serial ports use this mode to
implement unidirectional flow control. The serial port will suspend transmission
when requested by the modem (via CTS) but will be unable to request the modem stop
sending to the computer. This mode retains the ability to use DTR as a modem
control line.
defaultroute
當IPCP協商完全成功時，增加一個預設遞送路徑到系統 的遞送表，將彼端當作閘道器使
用。這個專案在ppp連線 中斷後會移除。
disconnect script
在pppd已經終結該連線之後執行以所指定的可執行 指令或是shell指令。這個指令稿可以用
來，例如，如果 硬體的資料機控制訊號無法使用時，發出指令給資料機使 其結束通話電話。
The disconnect script is not run if the modem has already hung up. A value for
this option from a privileged source cannot be overridden by a non-privileged user.
escape xx,yy,...
指定在傳輸上確實應該要避開的字元（不管對方是否有用 它的非同步控制字元對照表要求避
開它們）。這些要被避 開的字元是以用逗號隔開的一串十六進位數字指定的。要 注意到幾乎
任何字元都可以用escape選項指定避開，不 像asyncmap選項只允許指定控制字元。不能避開的
字元 是那些有十六進位值0x20-0x3f或是0x5e者。
file name
從檔案裡讀取選項（其格式敘述在後） The file must be readable by the user who has
invoked pppd.
init script
Run the executable or shell command specified by script to initialize the serial
line. This script would typically use the chat(8) program to configure the modem
to enable auto answer. A value for this option from a privileged source cannot be
overridden by a non-privileged user.
lock 指定pppd應該在此串列裝置上使用UUCP式的鎖定以確 定對該裝置為互斥(exclusive)存取。
mru n 把MRU[MaximumReceiveUnit最大接收單元]的值設為 n來進行協商。pppd將會要求彼端傳送不比
位元組 更長的封包。最小的MRU值是128。預設的MRU值則是 1500。對於慢速線路上的建議值
是296（其中40個位元 組給TCP/IP表頭+256個位元組的資料）。
(Note that for IPv6 MRU must be at least 1280)
mtu n
將MTU[MaximumTransmitUnit最大傳輸單元]的值設 為n。除非彼端經由MRU協商要求一個更小
的值，pppd 將會要求核心網路程式碼透過PPP網路介面所傳送的資料 封包不超過n個位元組。
(Note that for IPv6 MTU must be at least 1280)
passive
在LCP中開啟"passive"選項。加上這個選項，pppd將 會試圖初使一個連線；如果沒有從彼端
接收到回應，那麼 pppd將只會被動地等待從彼端所傳來的一個有效LCP封 包（代替結束離
開，就像它在沒有這個選項時所作的）。
選項 OPTIONS
<local_IP_address>:<remote_IP_address>
設定本地以及／或是遠端介面的IP位址。兩者之中的任 何一個都可以省略。該IP位址可以利
用主機名稱或者是 十進位數值加小數點符號指定(e.g.150.234.56.78)。 預設的本地位址是系
統的（第一個）IP位址（除非有加上 noipdefault選項）。遠端位址如果沒有在任何選項中指
定的話將從彼端取得。因此，在簡單的案例中，這個選項 不是必須的。如果有一個本地以
及／或是遠端的IP位址 以這個選項加以指定的話，pppd將不會接受在IPCP協商 中從彼端所傳
來不同的值，除非加上ipcp-accept-local 以及／或是ipcp-accept-remote選項，個別地。
ipv6 <local_interface_identifier>,<remote_interface_identifier>
Set the local and/or remote 64-bit interface identifier. Either one may be omitted.
The identifier must be specified in standard ascii notation of IPv6 addresses (e.g.
::dead:beef). If the ipv6cp-use-ipaddr option is given, the local identifier is the
local IPv4 address (see above). On systems which supports a unique persistent id,
such as EUI-48 derived from the Ethernet MAC address, ipv6cp-use-persistent option
can be used to replace the ipv6 <local>,<remote> option. Otherwise the identifier
is randomized.
active-filter filter-expression
Specifies a packet filter to be applied to data packets to determine which packets
are to be regarded as link activity, and therefore reset the idle timer, or cause
the link to be brought up in demand-dialling mode. This option is useful in
conjunction with the idle option if there are packets being sent or received
regularly over the link (for example, routing information packets) which would
otherwise prevent the link from ever appearing to be idle. The filter-expression
syntax is as described for tcpdump(1), except that qualifiers which are
inappropriate for a PPP link, such as ether and arp, are not permitted. Generally
the filter expression should be enclosed in single-quotes to prevent whitespace in
the expression from being interpreted by the shell. This option is currently only
available under NetBSD, and then only if both the kernel and pppd were compiled
with PPP_FILTER defined.
allow-ip address(es)
Allow peers to use the given IP address or subnet without authenticating
themselves. The parameter is parsed as for each element of the list of allowed IP
addresses in the secrets files (see the AUTHENTICATION section below).
bsdcomp nr,nt
Request that the peer compress packets that it sends, using the BSD-Compress
scheme, with a maximum code size of nr bits, and agree to compress packets sent to
the peer with a maximum code size of nt bits. If nt is not specified, it defaults
to the value given for nr. Values in the range 9 to 15 may be used for nr and nt;
larger values give better compression but consume more kernel memory for
compression dictionaries. Alternatively, a value of 0 for nr or nt disables
compression in the corresponding direction. Use nobsdcomp or bsdcomp 0 to disable
BSD-Compress compression entirely.
cdtrcts
Use a non-standard hardware flow control (i.e. DTR/CTS) to control the flow of data
on the serial port. If neither the crtscts, the nocrtscts, the cdtrcts nor the
nocdtrcts option is given, the hardware flow control setting for the serial port is
left unchanged. Some serial ports (such as Macintosh serial ports) lack a true RTS
output. Such serial ports use this mode to implement true bi-directional flow
control. The sacrifice is that this flow control mode does not permit using DTR as
a modem control line.
chap-interval n
如果有給這個選項，pppd將會每n 秒重新盤查彼端。
chap-max-challenge n
將CHAP盤查(challenge)傳輸的最大數目設為n（預 設為10）。
chap-restart n
將CHAP重新開始的間隔（重新傳輸的時間限制）設為n 秒鐘（預設為3）。
connect-delay n
Wait for up n milliseconds after the connect script finishes for a valid PPP packet
from the peer. At the end of this time, or when a valid PPP packet is received
from the peer, pppd will commence negotiation by sending its first LCP packet. The
default value is 1000 (1 second). This wait period only applies if the connect or
pty option is used.
debug 遞增偵錯層級（與-d相同）。如果加上這個選項，pppd 將以可供閱讀的格式記錄所有傳送或接
收的控制封包內容。 這些封包透過syslog以facilitydaemon還有level debug加以記錄。該資
訊可以適當設定/etc/syslog.conf 來導向到一個檔案去。（參閱syslog.conf(5)）。(如果
pppd以開啟擴充偵錯(extradebugging)編譯的話，它將 會使用facilitylocal2取代daemon來記
錄訊息）。
default-asyncmap
Disable asyncmap negotiation, forcing all control characters to be escaped for both
the transmit and the receive direction.
default-mru
Disable MRU [Maximum Receive Unit] negotiation. With this option, pppd will use
the default MRU value of 1500 bytes for both the transmit and receive direction.
deflate nr,nt
Request that the peer compress packets that it sends, using the Deflate scheme,
with a maximum window size of 2**nr bytes, and agree to compress packets sent to
the peer with a maximum window size of 2**nt bytes. If nt is not specified, it
defaults to the value given for nr. Values in the range 9 to 15 may be used for nr
and nt; larger values give better compression but consume more kernel memory for
compression dictionaries. Alternatively, a value of 0 for nr or nt disables
compression in the corresponding direction. Use nodeflate or deflate 0 to disable
Deflate compression entirely. (Note: pppd requests Deflate compression in
preference to BSD-Compress if the peer can do either.)
demand Initiate the link only on demand, i.e. when data traffic is present. With this
option, the remote IP address must be specified by the user on the command line or
in an options file. Pppd will initially configure the interface and enable it for
IP traffic without connecting to the peer. When traffic is available, pppd will
connect to the peer and perform negotiation, authentication, etc. When this is
completed, pppd will commence passing data packets (i.e., IP packets) across the
link.
The demand option implies the persist option. If this behaviour is not desired,
use the nopersist option after the demand option. The idle and holdoff options are
also useful in conjuction with the demand option.
domain d
新增領域名稱到本地主機名稱以支援驗證。例如，如 果gethostname()回應porsche這個名
稱，但是完整合 格的領域名稱是porsche.Quotron.COM的話，你可以使用 domain選項來將領域
名稱設為Quotron.COM。
Pppd would then use the name porsche.Quotron.COM for looking up secrets in the
secrets file, and as the default name to send to the peer when authenticating
itself to the peer. This option is privileged.
dryrun With the dryrun option, pppd will print out all the option values which have been
set and then exit, after parsing the command line and options files and checking
the option values, but before initiating the link. The option values are logged at
level info, and also printed to standard output unless the device on standard
output is the device that pppd would be using to communicate with the peer.
dump With the dump option, pppd will print out all the option values which have been
set. This option is like the dryrun option except that pppd proceeds as normal
rather than exiting.
endpoint <epdisc>
Sets the endpoint discriminator sent by the local machine to the peer during
multilink negotiation to <epdisc>. The default is to use the MAC address of the
first ethernet interface on the system, if any, otherwise the IPv4 address
corresponding to the hostname, if any, provided it is not in the multicast or
locally-assigned IP address ranges, or the localhost address. The endpoint
discriminator can be the string null or of the form type:value, where type is a
decimal number or one of the strings local, IP, MAC, magic, or phone. The value is
an IP address in dotted-decimal notation for the IP type, or a string of bytes in
hexadecimal, separated by periods or colons for the other types. For the MAC type,
the value may also be the name of an ethernet or similar network interface. This
option is currently only available under Linux.
hide-password
When logging the contents of PAP packets, this option causes pppd to exclude the
password string from the log. This is the default.
holdoff n
Specifies how many seconds to wait before re-initiating the link after it
terminates. This option only has any effect if the persist or demand option is
used. The holdoff period is not applied if the link was terminated because it was
idle.
idle n Specifies that pppd should disconnect if the link is idle for n seconds. The link
is idle when no data packets (i.e. IP packets) are being sent or received. Note:
it is not advisable to use this option with the persist option without the demand
option. If the active-filter option is given, data packets which are rejected by
the specified activity filter also count as the link being idle.
ipcp-accept-local
加上這個選項的話，pppd將會接受彼端對於本地IP位址 的意見，即使本地的IP位址已經在某個
選項中指定。
ipcp-accept-remote
加上這個選項的話，pppd將會接受彼端對於它的IP位址 的意見，即使遠端的IP位址已經在某個
選項中指定。
ipcp-max-configure n
將IPCP配置要求(configure-request)傳輸的最大數目設 為n（預設為10）。
ipcp-max-failure n
將開始傳送配置拒絕(configure-Rejects)之前的IPCP配 置未接收(configure-NAKs)的最大數
目以取代n（預設 為10）。
ipcp-max-terminate n
將IPCP終結要求(terminate-request)傳輸的最大數目設 為 n（預設為3）。
ipcp-restart n
將IPCP重新開始的間隔（重新傳輸的時間限制）設為n 秒鐘（預設為3）。
ipparam string
Provides an extra parameter to the ip-up and ip-down scripts. If this option is
given, the string supplied is given as the 6th parameter to those scripts.
ipv6cp-max-configure n
Set the maximum number of IPv6CP configure-request transmissions to n (default 10).
ipv6cp-max-failure n
Set the maximum number of IPv6CP configure-NAKs returned before starting to send
configure-Rejects instead to n (default 10).
ipv6cp-max-terminate n
Set the maximum number of IPv6CP terminate-request transmissions to n (default 3).
ipv6cp-restart n
Set the IPv6CP restart interval (retransmission timeout) to n seconds (default 3).
ipx Enable the IPXCP and IPX protocols. This option is presently only supported under
Linux, and only if your kernel has been configured to include IPX support.
ipx-network n
Set the IPX network number in the IPXCP configure request frame to n, a hexadecimal
number (without a leading 0x). There is no valid default. If this option is not
specified, the network number is obtained from the peer. If the peer does not have
the network number, the IPX protocol will not be started.
ipx-node n:m
Set the IPX node numbers. The two node numbers are separated from each other with a
colon character. The first number n is the local node number. The second number m
is the peer's node number. Each node number is a hexadecimal number, at most 10
digits long. The node numbers on the ipx-network must be unique. There is no valid
default. If this option is not specified then the node numbers are obtained from
the peer.
ipx-router-name <string>
Set the name of the router. This is a string and is sent to the peer as information
data.
ipx-routing n
Set the routing protocol to be received by this option. More than one instance of
ipx-routing may be specified. The 'none' option (0) may be specified as the only
instance of ipx-routing. The values may be 0 for NONE, 2 for RIP/SAP, and 4 for
NLSP.
ipxcp-accept-local
Accept the peer's NAK for the node number specified in the ipx-node option. If a
node number was specified, and non-zero, the default is to insist that the value be
used. If you include this option then you will permit the peer to override the
entry of the node number.
ipxcp-accept-network
Accept the peer's NAK for the network number specified in the ipx-network option.
If a network number was specified, and non-zero, the default is to insist that the
value be used. If you include this option then you will permit the peer to override
the entry of the node number.
ipxcp-accept-remote
Use the peer's network number specified in the configure request frame. If a node
number was specified for the peer and this option was not specified, the peer will
be forced to use the value which you have specified.
ipxcp-max-configure n
Set the maximum number of IPXCP configure request frames which the system will send
to n. The default is 10.
ipxcp-max-failure n
Set the maximum number of IPXCP NAK frames which the local system will send before
it rejects the options. The default value is 3.
ipxcp-max-terminate n
Set the maximum nuber of IPXCP terminate request frames before the local system
considers that the peer is not listening to them. The default value is 3.
kdebug n
開啟核心層級中的PPP驅動程式偵錯碼。The argument values depend on the specific
kernel driver, but in general a value of 1 will enable general kernel debug
messages. (Note that these messages are usually only useful for debugging the
kernel driver itself.) For the Linux 2.2.x kernel driver, 引數n是一個 由下列值所組
合的數字：1開啟一般偵錯訊息，2要求印 出所接收到的封包內容，而4要求印出傳輸的封包內
容。 On most systems, messages printed by the kernel are logged by syslog(1) to a
file as directed in the /etc/syslog.conf configuration file.
ktune Enables pppd to alter kernel settings as appropriate. Under Linux, pppd will
enable IP forwarding (i.e. set /proc/sys/net/ipv4/ip_forward to 1) if the proxyarp
option is used, and will enable the dynamic IP address option (i.e. set
/proc/sys/net/ipv4/ip_dynaddr to 1) in demand mode if the local address changes.
lcp-echo-failure n
如果有給這個選項，那麼如果傳送n個LCP回應要求沒 有接收到有效的LCP回應回覆的話pppd將
會推測彼端是 死掉的。如果發生這種情形，pppd將會終結該連線。這個 選項的使用要求一個
非零的lcp-echo-interval引數值。 這個選項可以用在硬體資料機控制線路無法使用的情況下
當實際連線被中斷之後（e.g.,資料機已經結束通話）終結 pppd的執行。
lcp-echo-interval n
如果有給這個選項，pppd每秒將會送出一個LCP回 應要求(echo-request)封包(frame)給彼
端。在Linux系 統下，回應要求在n秒內沒有從彼端接收到封包時會被送 出。一般彼端應該以
傳送一個回應回覆(echo-reply)來反 應該回應要求。這個選項可以與lcp-echo-failure選項
一起使用來偵測不再連線的彼端。
lcp-max-configure n
將LCP配置要求(configure-request)傳輸的最大數目設 為n（預設為10）。
lcp-max-failure n
將開始傳送配置拒絕(configure-Rejects)之前的LCP配 置未接收(configure-NAKs)的最大數
目設定為n（預設 為10）。
lcp-max-terminate n
將LCP終結要求(terminate-request)傳輸的最大數目設 為n（預設為3）。
lcp-restart n
將LCP重新開始的間隔（重新傳輸的時間限制）設為 秒鐘（預設為3）。
linkname name
Sets the logical name of the link to name. Pppd will create a file named ppp-
name.pid in /var/run (or /etc/ppp on some systems) containing its process ID. This
can be useful in determining which instance of pppd is responsible for the link to
a given peer system. This is a privileged option.
local 不要使用資料機控制線路。 With this option, pppd will ignore the state of the CD
(Carrier Detect) signal from the modem and will not change the state of the DTR
(Data Terminal Ready) signal.
logfd n
Send log messages to file descriptor n. Pppd will send log messages to at most one
file or file descriptor (as well as sending the log messages to syslog), so this
option and the logfile option are mutually exclusive. The default is for pppd to
send log messages to stdout (file descriptor 1), unless the serial port is already
open on stdout.
logfile filename
Append log messages to the file filename (as well as sending the log messages to
syslog). The file is opened with the privileges of the user who invoked pppd, in
append mode.
login 使用系統密碼資料庫驗證使用PAP的彼端。 and record the user in the system wtmp file.
Note that the peer must have an entry in the /etc/ppp/pap-secrets file as well as
the system password database to be allowed access.
maxconnect n
Terminate the connection when it has been available for network traffic for n
seconds (i.e. n seconds after the first network control protocol comes up).
maxfail n
Terminate after n consecutive failed connection attempts. A value of 0 means no
limit. The default value is 10.
modem 使用資料機控制線路。This option is the default. With this option, pppd will wait
for the CD (Carrier Detect) signal from the modem to be asserted when opening the
serial device (unless a connect script is specified), and it will drop the DTR
(Data Terminal Ready) signal briefly when the connection is terminated and before
executing the connect script. 在Ultrix上，這個選項會實作硬 體流量控制，像crtsct選項
作的。
mp Enables the use of PPP multilink; this is an alias for the `multilink' option.
This option is currently only available under Linux.
mpshortseq
Enables the use of short (12-bit) sequence numbers in multilink headers, as opposed
to 24-bit sequence numbers. This option is only available under Linux, and only
has any effect if multilink is enabled (see the multilink option).
mrru n Sets the Maximum Reconstructed Receive Unit to n. The MRRU is the maximum size for
a received packet on a multilink bundle, and is analogous to the MRU for the
individual links. This option is currently only available under Linux, and only
has any effect if multilink is enabled (see the multilink option).
ms-dns <addr>
If pppd is acting as a server for Microsoft Windows clients, this option allows
pppd to supply one or two DNS (Domain Name Server) addresses to the clients. The
first instance of this option specifies the primary DNS address; the second
instance (if given) specifies the secondary DNS address. (This option was present
in some older versions of pppd under the name dns-addr.)
ms-wins <addr>
If pppd is acting as a server for Microsoft Windows or "Samba" clients, this option
allows pppd to supply one or two WINS (Windows Internet Name Services) server
addresses to the clients. The first instance of this option specifies the primary
WINS address; the second instance (if given) specifies the secondary WINS address.
multilink
Enables the use of the PPP multilink protocol. If the peer also supports
multilink, then this link can become part of a bundle between the local system and
the peer. If there is an existing bundle to the peer, pppd will join this link to
that bundle, otherwise pppd will create a new bundle. See the MULTILINK section
below. This option is currently only available under Linux.
name name
將本地系統的名稱設為用來進行驗證。 This is a privileged option. With this option,
pppd will use lines in the secrets files which have name as the second field when
looking for a secret to use in authenticating the peer. In addition, unless
overridden with the user option, name will be used as the name to send to the peer
when authenticating the local system to the peer. (Note that pppd does not append
the domain name to name.)
netmask n
把該介面網路掩碼設為，這是一個以″十進位數值加 小數點″("decimaldot")符號表示的32位
元網路掩碼 (e.g.255.255.255.0)。If this option is given, the value specified is
ORed with the default netmask. The default netmask is chosen based on the
negotiated remote IP address; it is the appropriate network mask for the class of
the remote IP address, ORed with the netmasks for any non point-to-point network
interfaces in the system which are on the same network. (Note: on some platforms,
pppd will always use 255.255.255.255 for the netmask, if that is the only
appropriate value for a point-to-point interface.)
noaccomp
Disable Address/Control compression in both directions (send and receive).
noauth Do not require the peer to authenticate itself. This option is privileged.
nobsdcomp
Disables BSD-Compress compression; pppd will not request or agree to compress
packets using the BSD-Compress scheme.
noccp Disable CCP (Compression Control Protocol) negotiation. This option should only be
required if the peer is buggy and gets confused by requests from pppd for CCP
negotiation.
nocrtscts
Disable hardware flow control (i.e. RTS/CTS) on the serial port. If neither the
crtscts nor the nocrtscts nor the cdtrcts nor the nocdtrcts option is given, the
hardware flow control setting for the serial port is left unchanged.
nocdtrcts
This option is a synonym for nocrtscts. Either of these options will disable both
forms of hardware flow control.
nodefaultroute
Disable the defaultroute option. The system administrator who wishes to prevent
users from creating default routes with pppd can do so by placing this option in
the /etc/ppp/options file.
nodeflate
Disables Deflate compression; pppd will not request or agree to compress packets
using the Deflate scheme.
nodetach
Don't detach from the controlling terminal. Without this option, if a serial
device other than the terminal on the standard input is specified, pppd will fork
to become a background process.
noendpoint
Disables pppd from sending an endpoint discriminator to the peer or accepting one
from the peer (see the MULTILINK section below). This option should only be
required if the peer is buggy.
noip Disable IPCP negotiation and IP communication. This option should only be required
if the peer is buggy and gets confused by requests from pppd for IPCP negotiation.
noipv6 Disable IPv6CP negotiation and IPv6 communication. This option should only be
required if the peer is buggy and gets confused by requests from pppd for IPv6CP
negotiation.
noipdefault
關閉在沒有指定本地IP位址時所進行的預設動作，這是 用來由從主機名稱決定（如果可能的
話）決定本地IP位 址。加上這個選項的話，彼端將必須在進行IPCP協商時 （除非在指令列或
在選項檔中明確地指定它）提供本地的 IP位址。
noipx Disable the IPXCP and IPX protocols. This option should only be required if the
peer is buggy and gets confused by requests from pppd for IPXCP negotiation.
noktune
Opposite of the ktune option; disables pppd from changing system settings.
nolog Do not send log messages to a file or file descriptor. This option cancels the
logfd and logfile options.
nomagic
Disable magic number negotiation. With this option, pppd cannot detect a looped-
back line. This option should only be needed if the peer is buggy.
nomp Disables the use of PPP multilink. This option is currently only available under
Linux.
nompshortseq
Disables the use of short (12-bit) sequence numbers in the PPP multilink protocol,
forcing the use of 24-bit sequence numbers. This option is currently only
available under Linux, and only has any effect if multilink is enabled.
nomultilink
Disables the use of PPP multilink. This option is currently only available under
Linux.
nopcomp
Disable protocol field compression negotiation in both the receive and the transmit
direction.
nopersist
Exit once a connection has been made and terminated. This is the default unless
the persist or demand option has been specified.
nopredictor1
Do not accept or agree to Predictor-1 compression.
noproxyarp
Disable the proxyarp option. The system administrator who wishes to prevent users
from creating proxy ARP entries with pppd can do so by placing this option in the
/etc/ppp/options file.
notty Normally, pppd requires a terminal device. With this option, pppd will allocate
itself a pseudo-tty master/slave pair and use the slave as its terminal device.
Pppd will create a child process to act as a `character shunt' to transfer
characters between the pseudo-tty master and its standard input and output. Thus
pppd will transmit characters on its standard output and receive characters on its
standard input even if they are not terminal devices. This option increases the
latency and CPU overhead of transferring data over the ppp interface as all of the
characters sent and received must flow through the character shunt process. An
explicit device name may not be given if this option is used.
novj Disable Van Jacobson style TCP/IP header compression in both the transmit and the
receive direction.
novjccomp
Disable the connection-ID compression option in Van Jacobson style TCP/IP header
compression. With this option, pppd will not omit the connection-ID byte from Van
Jacobson compressed TCP/IP headers, nor ask the peer to do so.
papcrypt
Indicates that all secrets in the /etc/ppp/pap-secrets file which are used for
checking the identity of the peer are encrypted, and thus pppd should not accept a
password which, before encryption, is identical to the secret from the
/etc/ppp/pap-secrets file.
pap-max-authreq n
將PAP驗證要求(authenticate-request)傳輸的最大數目 設為n（預設為10）。
pap-restart n
將PAP重新開始的間隔（重新傳輸的時間限制）設為n 秒鐘（預設為3）。
pap-timeout n
Set the maximum time that pppd will wait for the peer to authenticate itself with
PAP to n seconds (0 means no limit).
pass-filter filter-expression
Specifies a packet filter to applied to data packets being sent or received to
determine which packets should be allowed to pass. Packets which are rejected by
the filter are silently discarded. This option can be used to prevent specific
network daemons (such as routed) using up link bandwidth, or to provide a basic
firewall capability. The filter-expression syntax is as described for tcpdump(1),
except that qualifiers which are inappropriate for a PPP link, such as ether and
arp, are not permitted. Generally the filter expression should be enclosed in
single-quotes to prevent whitespace in the expression from being interpreted by the
shell. Note that it is possible to apply different constraints to incoming and
outgoing packets using the inbound and outbound qualifiers. This option is
currently only available under NetBSD, and then only if both the kernel and pppd
were compiled with PPP_FILTER defined.
persist
Do not exit after a connection is terminated; instead try to reopen the connection.
plugin filename
Load the shared library object file filename as a plugin. This is a privileged
option.
predictor1
Request that the peer compress frames that it sends using Predictor-1 compression,
and agree to compress transmitted frames with Predictor-1 if requested. This
option has no effect unless the kernel driver supports Predictor-1 compression.
privgroup group-name
Allows members of group group-name to use privileged options. This is a privileged
option. Use of this option requires care as there is no guarantee that members of
group-name cannot use pppd to become root themselves. Consider it equivalent to
putting the members of group-name in the kmem or disk group.
proxyarp
以彼端的IP位址以及該系統的乙太網路位址增加一個項 目到系統
的ARP[AddressResolutionProtocol位址解 譯協定]表格。 This will have the effect of
making the peer appear to other systems to be on the local ethernet.
pty script
Specifies that the command script is to be used to communicate rather than a
specific terminal device. Pppd will allocate itself a pseudo-tty master/slave pair
and use the slave as its terminal device. The script will be run in a child
process with the pseudo-tty master as its standard input and output. An explicit
device name may not be given if this option is used. (Note: if the record option
is used in conjuction with the pty option, the child process will have pipes on its
standard input and output.)
receive-all
With this option, pppd will accept all control characters from the peer, including
those marked in the receive asyncmap. Without this option, pppd will discard those
characters as specified in RFC1662. This option should only be needed if the peer
is buggy.
record filename
Specifies that pppd should record all characters sent and received to a file named
filename. This file is opened in append mode, using the user's user-ID and
permissions. This option is implemented using a pseudo-tty and a process to
transfer characters between the pseudo-tty and the real serial device, so it will
increase the latency and CPU overhead of transferring data over the ppp interface.
The characters are stored in a tagged format with timestamps, which can be
displayed in readable form using the pppdump(8) program.
remotename name
將遠端系統的假設名稱設為以進行驗證。
refuse-chap
With this option, pppd will not agree to authenticate itself to the peer using
CHAP.
refuse-pap
With this option, pppd will not agree to authenticate itself to the peer using PAP.
require-chap
Require the peer to authenticate itself using CHAP [Challenge Handshake
Authentication Protocol] authentication.
require-pap
Require the peer to authenticate itself using PAP [Password Authentication
Protocol] authentication.
show-password
When logging the contents of PAP packets, this option causes pppd to show the
password string in the log message.
silent 加上這個選項，pppd將不會傳輸LCP封包來初使一個連 線一直到從彼端接收到一個有效的LCP封
包。（就像是給 舊版pppd使用的"passive"選項）。
sync Use synchronous HDLC serial encoding instead of asynchronous. The device used by
pppd with this option must have sync support. Currently supports Microgate
SyncLink adapters under Linux and FreeBSD 2.2.8 and later.
updetach
With this option, pppd will detach from its controlling terminal once it has
successfully established the ppp connection (to the point where the first network
control protocol, usually the IP control protocol, has come up).
usehostname
強迫主機名稱使用本地系統的名稱來進行驗證。（這會蓋過name選項）。 This option is not
normally needed since the name option is privileged.
usepeerdns
Ask the peer for up to 2 DNS server addresses. The addresses supplied by the peer
(if any) are passed to the /etc/ppp/ip-up script in the environment variables DNS1
and DNS2. In addition, pppd will create an /etc/ppp/resolv.conf file containing
one or two nameserver lines with the address(es) supplied by the peer.
user name
將使用者名稱設為以便讓使用PAP的彼端驗證這臺機器時使用。
vj-max-slots n
Sets the number of connection slots to be used by the Van Jacobson TCP/IP header
compression and decompression code to n, which must be between 2 and 16
(inclusive).
welcome script
Run the executable or shell command specified by script before initiating PPP
negotiation, after the connect script (if any) has completed. A value for this
option from a privileged source cannot be overridden by a non-privileged user.
xonxoff
使用軟體流量控制(i.e.XON/XOFF)來控制串列埠上的資料流。
選項檔案 OPTIONS FILES
選項可以從檔案取出使用就如同使用命令列一般。pppd在檢視指 令列之前先從檔
案/etc/ppp/options以及~/.ppprc讀取選項。 ttyname (in that order) before processing the
options on the command line. (In fact, the command-line options are scanned to find the
terminal name before the options.ttyname file is read.) In forming the name of the
options.ttyname file, the initial /dev/ is removed from the terminal name, and any
remaining / characters are replaced with dots.
一個選項檔案以空白字元為界被剖析成一串單字。空白字元可以用 雙引號(")包括在一個單字裡。倒斜
線引用其後的字元。而hash (#)符號開始一段註解持續到該行結束。 There is no restriction on
using the file or call options within an options file.
安全 SECURITY
pppd 提供系統管理人員充份的存取控制能力這表示以PPP存取一 臺伺服機器可以提供給合法的使用者
使用而不必擔心危及該伺服器 或所在網路的安全性。這有一部份是以/etc/ppp/options檔案來 提
供，在這裡系統管理人員可以放置在執行pppd的時候用來要求 驗證的選項，而部份是由PAP以及CHAP暗
號檔案來提供，其中 系統管理人員可以限制個別的使用者可以使用的一群IP位址。
The default behaviour of pppd is to allow an unauthenticated peer to use a given IP
address only if the system does not already have a route to that IP address. For example,
a system with a permanent connection to the wider internet will normally have a default
route, and thus all peers will have to authenticate themselves in order to set up a
connection. On such a system, the auth option is the default. On the other hand, a
system where the PPP link is the only connection to the internet will not normally have a
default route, so the peer will be able to use almost any IP address without
authenticating itself.
As indicated above, some security-sensitive options are privileged, which means that they
may not be used by an ordinary non-privileged user running a setuid-root pppd, either on
the command line, in the user's ~/.ppprc file, or in an options file read using the file
option. Privileged options may be used in /etc/ppp/options file or in an options file
read using the call option. If pppd is being run by the root user, privileged options can
be used without restriction.
When opening the device, pppd uses either the invoking user's user ID or the root UID
(that is, 0), depending on whether the device name was specified by the user or the system
administrator. If the device name comes from a privileged source, that is,
/etc/ppp/options or an options file read using the call option, pppd uses full root
privileges when opening the device. Thus, by creating an appropriate file under
/etc/ppp/peers, the system administrator can allow users to establish a ppp connection via
a device which they would not normally have permission to access. Otherwise pppd uses the
invoking user's real UID when opening the device.
AUTHENTICATION
Authentication is the process whereby one peer convinces the other of its identity. This
involves the first peer sending its name to the other, together with some kind of secret
information which could only come from the genuine authorized user of that name. In such
an exchange, we will call the first peer the "client" and the other the "server". The
client has a name by which it identifies itself to the server, and the server also has a
name by which it identifies itself to the client. Generally the genuine client shares
some secret (or password) with the server, and authenticates itself by proving that it
knows that secret. Very often, the names used for authentication correspond to the
internet hostnames of the peers, but this is not essential.
At present, pppd supports two authentication protocols: the Password Authentication
Protocol (PAP) and the Challenge Handshake Authentication Protocol (CHAP). PAP involves
the client sending its name and a cleartext password to the server to authenticate itself.
In contrast, the server initiates the CHAP authentication exchange by sending a challenge
to the client (the challenge packet includes the server's name). The client must respond
with a response which includes its name plus a hash value derived from the shared secret
and the challenge, in order to prove that it knows the secret.
The PPP protocol, being symmetrical, allows both peers to require the other to
authenticate itself. In that case, two separate and independent authentication exchanges
will occur. The two exchanges could use different authentication protocols, and in
principle, different names could be used in the two exchanges.
pppd預設的動作是如果有要求就同意進行驗證，並且不要求從彼 端做驗證。然而如果沒有可以用來驗
證的暗號則pppd將不會同意 以特殊的協定來驗證它自己。
驗證的基礎是由暗號檔案選擇的暗號（/etc/ppp/pap-secrets是 給PAP使用的，/etc/ppp/chap-
secrets則是給CHAP使用）。 這兩個暗號檔案都具有相同的格式，而且兩者都可以儲放暗號給數 種伺
服器（驗證彼端）及客戶（被驗證端）組合使用。注意pppd 可以最為伺服端以及客戶端，而且如果需
要的話兩方可以使用不同 的協定。
一個暗號檔案如同選項檔案一般被剖析成單字。一個暗號是由最少 包含3個單字的一行所指定，依序
是客戶，伺服器，暗號。在同 一行中任何跟在其後的單字都被當作是給客戶的可接受IP位址列 表。如
果該行只有3個單字，這假設任何IP位址都可以；不允 許所有的IP位址的話，使用"-"。如果暗號是
以'@'開始，其 後所接的單字將被假設為可以從中讀取暗號的檔案名稱。而以一個 "*"字元作為客戶或
伺服端的名稱會符合任何名稱。在選擇一個暗 號時，pppd會選擇最符合的，i.e.最少萬用字元的那
個。
如此一個暗號檔案包含用來驗證其它主機，以及用來為其它主機驗 證自己兩者的暗號。選擇使用哪個
暗號是根據該主機（本地名稱） 以及其彼端（遠端名稱）而定。本地名稱的設定如下：
If the secret starts with an `@', what follows is assumed to be the name of a file from
which to read the secret. A "*" as the client or server name matches any name. When
selecting a secret, pppd takes the best match, i.e. the match with the fewest wildcards.
Any following words on the same line are taken to be a list of acceptable IP addresses for
that client. If there are only 3 words on the line, or if the first word is "-", then all
IP addresses are disallowed. To allow any address, use "*". A word starting with "!"
indicates that the specified address is not acceptable. An address may be followed by "/"
and a number n, to indicate a whole subnet, i.e. all addresses which have the same value
in the most significant n bits. In this form, the address may be followed by a plus sign
("+") to indicate that one address from the subnet is authorized, based on the ppp network
interface unit number in use. In this case, the host part of the address will be set to
the unit number plus one.
Thus a secrets file contains both secrets for use in authenticating other hosts, plus
secrets which we use for authenticating ourselves to others. When pppd is authenticating
the peer (checking the peer's identity), it chooses a secret with the peer's name in the
first field and the name of the local system in the second field. The name of the local
system defaults to the hostname, with the domain name appended if the domain option is
used. This default can be overridden with the name option, except when the usehostname
option is used.
When pppd is choosing a secret to use in authenticating itself to the peer, it first
determines what name it is going to use to identify itself to the peer. This name can be
specified by the user with the user option. If this option is not used, the name defaults
to the name of the local system, determined as described in the previous paragraph. Then
pppd looks for a secret with this name in the first field and the peer's name in the
second field. Pppd will know the name of the peer if CHAP authentication is being used,
because the peer will have sent it in the challenge packet. However, if PAP is being
used, pppd will have to determine the peer's name from the options specified by the user.
The user can specify the peer's name directly with the remotename option. Otherwise, if
the remote IP address was specified by a name (rather than in numeric form), that name
will be used as the peer's name. Failing that, pppd will use the null string as the
peer's name.
當以PAP驗證彼端時，一個""暗號符合任何由彼端所提供密碼。 如果密碼不符合暗號，密碼被
以crypt()編碼並且再次檢查暗號； 因此驗證彼端的暗號可以編碼方式儲放。
如果指定有login選項， 使用者名稱以及密碼也會被以系統的密碼資料庫檢查。因此係統管 理人員可
以設定pap-secrets檔案以便只允許某些使用者以PPP 連線，並且限制每個使用者可以使用一些IP位
址。 Typically, when using the login option, the secret in /etc/ppp/pap-secrets would be
"", which will match any password supplied by the peer. This avoids the need to have the
same secret in two places.
驗證必須在IPCP（或任何其它網路控制協定）開始之前被完全地 滿足。如果驗證失敗，pppd將會終結
連線（關閉LCP）。如果 IPCP協商出一個無法接受的遠端主機IP位址，IPCP將會關閉。 IP封包只有
在IPCP開啟的時候才能傳送或接收。
即使本地主機一般會要求驗證，在某些案例中會希望允一些無法驗 證它們自己的主機連線並使用所限
制的IP位址其中之一。如果彼 在被要求時拒絕驗證它自己，pppd將會把它當成等於是在使用者 名稱以
及密碼上使用空字串來以PAP驗證。所以，藉由增加一行 指定空字串為客戶以及密碼到pap-secrets檔
案去，允許拒絕驗 證自己的主機進行有限制的存取是可能的。
路由 ROUTING
當IPCP協商成功地完成時，pppd將會通知核心該ppp介面本地 以及遠端的IP位址。這足夠用來建立一
個主機到該連線遠端的遞 送路徑，該路徑將使兩端能交換IP封包。與其它的機器進行通訊 往往需要更
進一步地修改遞送表格(routingtables)以及／或是 ARP（位址解譯協定）表格。在某些案例中這將透
過routed或是 gated隱形程式的動作自動地完成，但是在大部分的案例中需要更 進一步的介入。
有時候會希望透過遠端主機來增加一個預設遞送路徑，像是在一臺 只透過ppp介面連線到Internet的
機器。此defaultroute選 項使得pppd在IPCP完成時建立起這麼一個預設的遞送路徑，並 且在該線路被
終結時將之刪除。
在某些情況下會希望使用proxyARP，例如在一臺連結到區域網 路的伺服機器上，為了能夠允許其它的
主機與遠端主機進行通訊。 proxyarp選項引發pppd去尋找一個與遠端主機在相同子網路上 的網路介面
（一個支援廣播(boardcast)以及ARP的介面，不但要 是可用的並且不是一個點對點或回授介面）。如
果找到，pppd會 以該遠端主機的IP位址以及所找到的網路介面之硬體位址建立一 個永久的，公開
的ARP專案。
When the demand option is used, the interface IP addresses have already been set at the
point when IPCP comes up. If pppd has not been able to negotiate the same addresses that
it used to configure the interface (for example when the peer is an ISP that uses dynamic
IP address assignment), pppd has to change the interface IP addresses to the negotiated
addresses. This may disrupt existing connections, and the use of demand dialling with
peers that do dynamic IP address assignment is not recommended.
MULTILINK
Multilink PPP provides the capability to combine two or more PPP links between a pair of
machines into a single `bundle', which appears as a single virtual PPP link which has the
combined bandwidth of the individual links. Currently, multilink PPP is only supported
under Linux.
Pppd detects that the link it is controlling is connected to the same peer as another link
using the peer's endpoint discriminator and the authenticated identity of the peer (if it
authenticates itself). The endpoint discriminator is a block of data which is hopefully
unique for each peer. Several types of data can be used, including locally-assigned
strings of bytes, IP addresses, MAC addresses, randomly strings of bytes, or E-164 phone
numbers. The endpoint discriminator sent to the peer by pppd can be set using the
endpoint option.
In circumstances the peer may send no endpoint discriminator or a non-unique value. The
optional bundle option adds an extra string which is added to the peer's endpoint
discriminator and authenticated identity when matching up links to be joined together in a
bundle. The bundle option can also be used to allow the establishment of multiple bundles
between the local system and the peer. Pppd uses a TDB database in /var/run/pppd.tdb to
match up links.
Assuming that multilink is enabled and the peer is willing to negotiate multilink, then
when pppd is invoked to bring up the first link to the peer, it will detect that no other
link is connected to the peer and create a new bundle, that is, another ppp network
interface unit. When another pppd is invoked to bring up another link to the peer, it
will detect the existing bundle and join its link to it. Currently, if the first pppd
terminates (for example, because of a hangup or a received signal) the bundle is
destroyed.
範例 EXAMPLE S
The following examples assume that the /etc/ppp/options file contains the auth option (as
in the default /etc/ppp/options file in the ppp distribution).
Probably the most common use of pppd is to dial out to an ISP. This can be done with a
command such as
pppd call isp
where the /etc/ppp/peers/isp file is set up by the system administrator to contain
something like this:
ttyS0 19200 crtscts
connect '/usr/sbin/chat -v -f /etc/ppp/chat-isp'
noauth
In this example, we are using chat to dial the ISP's modem and go through any logon
sequence required. The /etc/ppp/chat-isp file contains the script used by chat; it could
for example contain something like this:
ABORT "NO CARRIER"
ABORT "NO DIALTONE"
ABORT "ERROR"
ABORT "NO ANSWER"
ABORT "BUSY"
ABORT "Username/Password Incorrect"
"" "at"
OK "at&d0&c1"
OK "atdt2468135"
"name:" "^Umyuserid"
"word:" "\qmypassword"
"ispts" "\q^Uppp"
"~-^Uppp-~"
See the chat(8) man page for details of chat scripts.
Pppd can also be used to provide a dial-in ppp service for users. If the users already
have login accounts, the simplest way to set up the ppp service is to let the users log in
to their accounts and run pppd (installed setuid-root) with a command such as
pppd proxyarp
To allow a user to use the PPP facilities, you need to allocate an IP address for that
user's machine and create an entry in /etc/ppp/pap-secrets or /etc/ppp/chap-secrets
(depending on which authentication method the PPP implementation on the user's machine
supports), so that the user's machine can authenticate itself. For example, if Joe has a
machine called "joespc" which is to be allowed to dial in to the machine called "server"
and use the IP address joespc.my.net, you would add an entry like this to /etc/ppp/pap-
secrets or /etc/ppp/chap-secrets:
joespc server "joe's secret" joespc.my.net
Alternatively, you can create a username called (for example) "ppp", whose login shell is
pppd and whose home directory is /etc/ppp. Options to be used when pppd is run this way
can be put in /etc/ppp/.ppprc.
如果你的串列連線比直接以線路連線更復雜的話，你可能會需要做 些調整以便避開一些控制字元。特
別是，通常避開XON(^Q)以及 XOFF(^S)是有用的，可以使用asyncmapa0000。如果該路徑包 含telnet的
話，你可能應該也要避開^](asyncmap200a0000)。 如果該路徑包含rlogin的話，你將需要在執
行rlogin的客戶端 上使用escapeff選項，因為許多rlogin的實作並非是透通的； 它們將會從資料流中
移除[0xff,0xff,0x73,0x73,跟隨的任何 8位元組]這些序列。
診斷 DIAGNOSTICS
訊息使用facilityLOG_DAEMON送到syslog隱形程式。（這個 可以藉著以所要的facility定
義LOG_PPP巨集來重新編譯pppd 加以改變。）為了能夠看到錯誤以及偵錯訊息，你將需要編輯你的
/etc/syslog.conf檔案來將訊息導向到所希望的裝置或檔案。
debug選項使得所有送出以及接收的控制封包內容都被記錄下來， 這是指所有的LCP,PAP,CHAP,或
是IPCP封包。如果PPP協商 沒有成功的話那麼這可能會有用。如果在編譯時期開啟偵錯功能的
話，pppd會使用facilityLOG_LOCAL2來取代LOG_DAEMON，而 且debug選項會使得額外的偵錯訊息被記錄
下來。
偵錯功能也可以藉著傳送一個SIGUSR1到pppd程式來啟動。偵 錯功能可以藉著傳送一
個SIGUSR2到pppd程式來關閉。
EXIT STATUS
The exit status of pppd is set to indicate whether any error was detected, or the reason
for the link being terminated. The values used are:
0 Pppd has detached, or otherwise the connection was successfully established and
terminated at the peer's request.
1 An immediately fatal error of some kind occurred, such as an essential system call
failing, or running out of virtual memory.
2 An error was detected in processing the options given, such as two mutually
exclusive options being used.
3 Pppd is not setuid-root and the invoking user is not root.
4 The kernel does not support PPP, for example, the PPP kernel driver is not included
or cannot be loaded.
5 Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP signal.
6 The serial port could not be locked.
7 The serial port could not be opened.
8 The connect script failed (returned a non-zero exit status).
9 The command specified as the argument to the pty option could not be run.
10 The PPP negotiation failed, that is, it didn't reach the point where at least one
network protocol (e.g. IP) was running.
11 The peer system failed (or refused) to authenticate itself.
12 The link was established successfully and terminated because it was idle.
13 The link was established successfully and terminated because the connect time limit
was reached.
14 Callback was negotiated and an incoming call should arrive shortly.
15 The link was terminated because the peer is not responding to echo requests.
16 The link was terminated by the modem hanging up.
17 The PPP negotiation failed because serial loopback was detected.
18 The init script failed (returned a non-zero exit status).
19 We failed to authenticate ourselves to the peer.
SCRIPTS
Pppd invokes scripts at various stages in its processing which can be used to perform
site-specific ancillary processing. These scripts are usually shell scripts, but could be
executable code files instead. Pppd does not wait for the scripts to finish. The scripts
are executed as root (with the real and effective user-id set to 0), so that they can do
things such as update routing tables or run privileged daemons. Be careful that the
contents of these scripts do not compromise your system's security. Pppd runs the scripts
with standard input, output and error redirected to /dev/null, and with an environment
that is empty except for some environment variables that give information about the link.
The environment variables that pppd sets are:
DEVICE The name of the serial tty device being used.
IFNAME The name of the network interface being used.
IPLOCAL
The IP address for the local end of the link. This is only set when IPCP has come
up.
IPREMOTE
The IP address for the remote end of the link. This is only set when IPCP has come
up.
PEERNAME
The authenticated name of the peer. This is only set if the peer authenticates
itself.
SPEED The baud rate of the tty device.
ORIG_UID
The real user-id of the user who invoked pppd.
PPPLOGNAME
The username of the real user-id that invoked pppd. This is always set.
For the ip-down and auth-down scripts, pppd also sets the following variables giving
statistics for the connection:
CONNECT_TIME
The number of seconds from when the PPP negotiation started until the connection
was terminated.
BYTES_SENT
The number of bytes sent (at the level of the serial port) during the connection.
BYTES_RCVD
The number of bytes received (at the level of the serial port) during the
connection.
LINKNAME
The logical name of the link, set with the linkname option.
Pppd invokes the following scripts, if they exist. It is not an error if they don't
exist.
/etc/ppp/auth-up
A program or script which is executed after the remote system successfully
authenticates itself. It is executed with the parameters
interface-name peer-name user-name tty-device speed
Note that this script is not executed if the peer doesn't authenticate itself, for
example when the noauth option is used.
/etc/ppp/auth-down
A program or script which is executed when the link goes down, if /etc/ppp/auth-up
was previously executed. It is executed in the same manner with the same
parameters as /etc/ppp/auth-up.
/etc/ppp/ip-up
當線路可以傳送以及接收IP封包時（也就是IPCP完成 時）執行的一支程式或指令稿。它是以介
面的名稱、終端 裝置、速度、本地-IP-位址、遠端-IP-位址為引數執行。
interface-name tty-device speed local-IP-address remote-IP-address ipparam
/etc/ppp/ip-down
當線路不再允許傳送以及接收IP封包時執行的一支程式 或指令稿。這個指令稿可以用來回
復/etc/ppp/ip-up指 令稿的影響。它以與ip-up指令稿相同的引數啟動。
/etc/ppp/ipv6-up
Like /etc/ppp/ip-up, except that it is executed when the link is available for
sending and receiving IPv6 packets. It is executed with the parameters
interface-name tty-device speed local-link-local-address remote-link-local-address
ipparam
/etc/ppp/ipv6-down
Similar to /etc/ppp/ip-down, but it is executed when IPv6 packets can no longer be
transmitted on the link. It is executed with the same parameters as the ipv6-up
script.
/etc/ppp/ipx-up
A program or script which is executed when the link is available for sending and
receiving IPX packets (that is, IPXCP has come up). It is executed with the
parameters
interface-name tty-device speed network-number local-IPX-node-address remote-IPX-
node-address local-IPX-routing-protocol remote-IPX-routing-protocol local-IPX-
router-name remote-IPX-router-name ipparam pppd-pid
The local-IPX-routing-protocol and remote-IPX-routing-protocol field may be one of
the following:
NONE to indicate that there is no routing protocol
RIP to indicate that RIP/SAP should be used
NLSP to indicate that Novell NLSP should be used
RIP NLSP to indicate that both RIP/SAP and NLSP should be used
/etc/ppp/ipx-down
A program or script which is executed when the link is no longer available for
sending and receiving IPX packets. This script can be used for undoing the effects
of the /etc/ppp/ipx-up script. It is invoked in the same manner and with the same
parameters as the ipx-up script.
檔案 FILES
/var/run/pppn.pid (BSD or Linux), /etc/ppp/pppn.pid (others)
在ppp介面單元n上的ppp程式之Process-ID。
/var/run/ppp-name.pid (BSD or Linux), /etc/ppp/ppp-name.pid (others)
Process-ID for pppd process for logical link name (see the linkname option).
/etc/ppp/pap-secrets
由PAP驗證所使用的使用者名稱、密碼以及IP位址。 This file should be owned by root
and not readable or writable by any other user. Pppd will log a warning if this is
not the case.
/etc/ppp/chap-secrets
由CHAP驗證所使用的名稱、暗號以及IP位址。
As for /etc/ppp/pap-secrets, this file should be owned by root and not readable or
writable by any other user. Pppd will log a warning if this is not the case.
/etc/ppp/options
pppd的系統預設選項，在使用者預設選項或指令列選項之前讀取。
~/.ppprc
使用者預設選項，在指令列選項之前讀取。
/etc/ppp/options.ttyname
所要使用之串列埠的系統預設選項，在指令列之後讀取。read after ~/.ppprc. In forming
the ttyname part of this filename, an initial /dev/ is stripped from the port name
(if present), and any slashes in the remaining part are converted to dots.
/etc/ppp/peers
A directory containing options files which may contain privileged options, even if
pppd was invoked by a user other than root. The system administrator can create
options files in this directory to permit non-privileged users to dial out without
requiring the peer to authenticate, but only to certain trusted peers.
參見 SEE ALSO
RFC1144
Jacobson, V. Compressing TCP/IP headers for low-speed serial links. February
1990.
RFC1321
Rivest, R. The MD5 Message-Digest Algorithm. April 1992.
RFC1332
McGregor, G. PPP Internet Protocol Control Protocol (IPCP). May 1992.
RFC1334
Lloyd, B.; Simpson, W.A. PPP authentication protocols. October 1992.
RFC1661
Simpson, W.A. The Point-to-Point Protocol (PPP). July 1994.
RFC1662
Simpson, W.A. PPP in HDLC-like Framing. July 1994.
RFC2472
Haskin, D. IP Version 6 over PPP December 1998.
注意 NOTES
下列訊號傳送到pppd程式時有特別的影響
SIGINT, SIGTERM
這些訊號使得pppd終止該連線（關閉LCP），回存串列 串列裝置的設定，並結束離開。
SIGHUP 指出實體層已經被斷線。pppd將會試圖回存串列裝置的設 定（這可能會在Suns上產生錯誤訊
息），然後結束離開。
If the persist or demand option has been specified, pppd will try to reopen the
serial device and start another connection (after the holdoff period). Otherwise
pppd will exit. If this signal is received during the holdoff period, it causes
pppd to end the holdoff period immediately.
SIGUSR1
This signal toggles the state of the debug option.
SIGUSR2
This signal causes pppd to renegotiate compression. This can be useful to re-
enable compression after it has been disabled as a result of a fatal decompression
error. (Fatal decompression errors generally indicate a bug in one or other
implementation.)
作者 AUTHOR S
Paul Mackerras (Paul.Mackerras@cs.anu.edu.au), based on earlier work by Drew Perkins, Brad
Clements, Karl Fox, Greg Christy, and Brad Parker.
[中文版維護人]
軟體教程之Linux Man <asdchen@pc2.hinet.net> <Best Linux> 1999
[中文版最新更新]
1995/10/08
《中國linux論壇man手冊頁翻譯計劃》:
http://cmpp.linuxforum.net
跋
本頁面中文版由中文 man 手冊頁計劃提供。
中文 man 手冊頁計劃：https://github.com/man-pages-zh/manpages-zh
PPPD(8)