Ubuntu Manpage: tayga.conf - configuration file of the TAYGA stateless NAT64 daemon

NAME

       tayga.conf - configuration file of the TAYGA stateless NAT64 daemon

DESCRIPTION

This file contains the configuration parameters for the TAYGA stateless NAT64 daemon. It
must exist and contain the mandatory configuration items or TAYGA will refuse to run.

The configuration directives are listed below. With the exception of the map directive,
only one instance of each directive may appear in tayga.conf.

tun-device device
Name of the network interface that will be created by the kernel TUN module for
TAYGA to exchange IPv4 and IPv6 packets with the in-kernel TCP/IP stack. If device
does not already exist as a persistent interface (created by the --mktun flag to
tayga(8), for example), it will be created automatically when the TAYGA daemon
starts and destroyed when the daemon exits.

Note that TAYGA does not configure the host-side parameters of device. This must
be done by the system administrator using the ifconfig(8), route(8), and/or ip(8)
commands.

This configuration directive is mandatory.

ipv4-addr ipv4_address
IPv4 address that TAYGA will use as the source address for ICMPv4 errors generated
by the translation process. TAYGA will also respond to ICMP echo requests (pings)
at this address.

ipv4_address is permitted to overlap with the prefix specified in the dynamic-pool
directive, in which case ipv4_address will be removed from the pool of available
addresses.

This configuration directive is mandatory.

ipv6-addr ipv6_address
IPv6 address that TAYGA will use as the source address for ICMPv6 errors generated
by the translation process. TAYGA will also respond to ICMPv6 echo requests
(pings) at this address.

This configuration directive is mandatory unless the NAT64 prefix is specified with
the prefix directive, in which case TAYGA will generate its IPv6 address by mapping
the address specified in ipv4-addr into the NAT64 prefix.

prefix ipv6_address/length
NAT64 prefix for mapping IPv4 addresses into the IPv6 address space. TAYGA
performs address translation as specified in RFC 6052, and only prefix lengths
allowed in that document will be permitted in the prefix directive.

The use of either a Network-Specific Prefix or the Well-Known Prefix (64:ff9b::/96)
is allowed, however, as required by RFC 6052, TAYGA will refuse to translate
packets with a source or destination address composed of the Well-Known Prefix and
a non-global IPv4 address (10.x.x.x, 192.168.x.x, etc).

Use of the prefix directive is optional. If it is not specified, all addresses to
be translated must be listed individually with the map directive.

map ipv4_address ipv6_address
Creates a static mapping between ipv4_address and ipv6_address to be used when
translating IPv4 packets to IPv6 or IPv6 packets to IPv4. Multiple map directives
are permitted in the tayga.conf file.

ipv4_address is permitted to overlap with the prefix specified in the dynamic-pool
directive, in which case ipv4_address will be removed from the pool of available
addresses.

ipv6_address must not overlap with the prefix specified in the prefix directive.

dynamic-pool ipv4_address/length
Address prefix containing addresses available to be assigned to IPv6 hosts. length
must be 31 or less, as the lowest-numbered address in the prefix is considered
reserved and will not be used for dynamic assignment.

If TAYGA receives an IPv6 packet to be translated with an IPv6 source address that
does not match any existing mapping rules (as specified by the map directive or the
prefix directive), TAYGA will create a dynamic mapping between the IPv6 address and
an IPv4 address drawn from the prefix specified by the dynamic-pool directive.
This mapping will be valid for two hours and four minutes after the last packet
matching the mapping is translated.

The dynamic-pool directive is optional. If it is not specified, all IPv6 addresses
appearing in packets passing through TAYGA must match the NAT64 prefix or a static
mapping rule.

data-dir path
The absolute path of a directory where TAYGA should store its data files.
Presently the only data file that TAYGA will store is the dynamic.map file, which
tracks dynamic address assignments made from the dynamic pool.

path is also the directory that will be used as a chroot(2) "jail" if the --chroot
command-line option is specified to the TAYGA daemon.

The TAYGA daemon must have full permissions (rwx) to path after it has dropped
superuser privileges. Generally this means that the owner of path should be the
user specified in the --user command-line option.

The data-dir directive is optional, but without it, dynamic mappings will be lost
when the TAYGA daemon is stopped. Also, use of the --chroot command-line option
will not be possible.

strict-frag-hdr on|off|true|false|1|0
Flag to control whether TAYGA adds fragmentation headers to IPv6 packets that do
not require fragmentation. RFC 6145 stipulates that the fragmentation header
SHOULD be added to all translated packets when the sender has not set the DF (Don't
Fragment) flag, to indicate that the sender allows fragmentation and may not
support path MTU discovery. Unfortunately, some firewall implementations drop IPv6
packets that are fragmented into a single fragment, most notably Linux netfilter
conntrack in kernels older than 2.6.34.

When strict-frag-hdr is set to true, on, or 1, fragmentation headers will be added
to all translated packets where the DF bit in the original packet is clear. This
is the RFC-complaint behavior.

When strict-frag-hdr is set to false, off, or 0, fragmentation headers will be
suppressed when the translated packet fits entirely within the IPv6 network MTU
(1280 bytes). This is the default behavior.

This setting does not affect packets that arrive at TAYGA already fragmented, or
packets that must be fragmented to fit within the IPv6 network MTU.

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