Provided by: iproute2_6.10.0-2_amd64 bug

NAME

       ss - another utility to investigate sockets

SYNOPSIS

       ss [options] [ FILTER ]

DESCRIPTION

       ss  is  used  to dump socket statistics. It allows showing information similar to netstat.
       It can display more TCP and state information than other tools.

OPTIONS

       When  no  option  is  used  ss  displays  a  list  of  open  non-listening  sockets  (e.g.
       TCP/UNIX/UDP) that have established connection.

       -h, --help
              Show summary of options.

       -V, --version
              Output version information.

       -H, --no-header
              Suppress header line.

       -Q, --no-queues
              Suppress sending and receiving queue columns.

       -O, --oneline
              Print each socket's data on a single line.

       -n, --numeric
              Do not try to resolve service names. Show exact bandwidth values, instead of human-
              readable.

       -r, --resolve
              Try to resolve numeric address/ports.

       -a, --all
              Display  both  listening  and  non-listening  (for  TCP  this   means   established
              connections) sockets.

       -l, --listening
              Display only listening sockets (these are omitted by default).

       -B, --bound-inactive
              Display  only  TCP  bound  but  inactive  (not listening, connecting, etc.) sockets
              (these are omitted by default).

       -o, --options
              Show timer information. For TCP protocol, the output format is:

              timer:(<timer_name>,<expire_time>,<retrans>)

              <timer_name>
                     the name of the timer, there are five kind of timer names:

                     on : means one of these timers: TCP retrans timer, TCP early  retrans  timer
                     and tail loss probe timer

                     keepalive: tcp keep alive timer

                     timewait: timewait stage timer

                     persist: zero window probe timer

                     unknown: none of the above timers

              <expire_time>
                     how long time the timer will expire

              <retrans>
                     how many times the retransmission occurred

       -e, --extended
              Show detailed socket information. The output format is:

              uid:<uid_number> ino:<inode_number> sk:<cookie>

              <uid_number>
                     the user id the socket belongs to

              <inode_number>
                     the socket's inode number in VFS

              <cookie>
                     an uuid of the socket

       -m, --memory
              Show socket memory usage. The output format is:

              skmem:(r<rmem_alloc>,rb<rcv_buf>,t<wmem_alloc>,tb<snd_buf>,
                            f<fwd_alloc>,w<wmem_queued>,o<opt_mem>,
                            bl<back_log>,d<sock_drop>)

              <rmem_alloc>
                     the memory allocated for receiving packet

              <rcv_buf>
                     the total memory can be allocated for receiving packet

              <wmem_alloc>
                     the memory used for sending packet (which has been sent to layer 3)

              <snd_buf>
                     the total memory can be allocated for sending packet

              <fwd_alloc>
                     the   memory   allocated   by   the  socket  as  cache,  but  not  used  for
                     receiving/sending packet yet. If need memory  to  send/receive  packet,  the
                     memory in this cache will be used before allocate additional memory.

              <wmem_queued>
                     The memory allocated for sending packet (which has not been sent to layer 3)

              <opt_mem>
                     The  memory  used  for  storing  socket  option,  e.g.,  the key for TCP MD5
                     signature

              <back_log>
                     The memory used for the sk backlog queue.  On  a  process  context,  if  the
                     process  is  receiving  packet, and a new packet is received, it will be put
                     into the sk backlog queue, so it can be received by the process immediately

              <sock_drop>
                     the number of packets dropped before they are de-multiplexed into the socket

       -p, --processes
              Show process using socket.

       -T, --threads
              Show thread using socket. Implies -p.

       -i, --info
              Show internal TCP information. Below fields may appear:

              ts     show string "ts" if the timestamp option is set

              sack   show string "sack" if the sack option is set

              ecn    show string "ecn" if the explicit congestion notification option is set

              ecnseen
                     show string "ecnseen" if the saw ecn flag is found in received packets

              fastopen
                     show string "fastopen" if the fastopen option is set

              cong_alg
                     the congestion algorithm name, the default congestion algorithm is "cubic"

              wscale:<snd_wscale>:<rcv_wscale>
                     if window scale option is used, this field shows the send scale  factor  and
                     receive scale factor

              rto:<icsk_rto>
                     tcp re-transmission timeout value, the unit is millisecond

              backoff:<icsk_backoff>
                     used  for  exponential  backoff  re-transmission, the actual re-transmission
                     timeout value is icsk_rto << icsk_backoff

              rtt:<rtt>/<rttvar>
                     rtt is the average round trip time, rttvar is the  mean  deviation  of  rtt,
                     their units are millisecond

              ato:<ato>
                     ack timeout, unit is millisecond, used for delay ack mode

              mss:<mss>
                     max segment size

              cwnd:<cwnd>
                     congestion window size

              pmtu:<pmtu>
                     path MTU value

              ssthresh:<ssthresh>
                     tcp congestion window slow start threshold

              bytes_acked:<bytes_acked>
                     bytes acked

              bytes_received:<bytes_received>
                     bytes received

              segs_out:<segs_out>
                     segments sent out

              segs_in:<segs_in>
                     segments received

              send <send_bps>bps
                     egress bps

              lastsnd:<lastsnd>
                     how long time since the last packet sent, the unit is millisecond

              lastrcv:<lastrcv>
                     how long time since the last packet received, the unit is millisecond

              lastack:<lastack>
                     how long time since the last ack received, the unit is millisecond

              pacing_rate <pacing_rate>bps/<max_pacing_rate>bps
                     the pacing rate and max pacing rate

              rcv_space:<rcv_space>
                     a helper variable for TCP internal auto tuning socket receive buffer

              tcp-ulp-mptcp     flags:[MmBbJjecv]     token:<rem_token(rem_id)/loc_token(loc_id)>
              seq:<sn> sfseq:<ssn> ssnoff:<off> maplen:<maplen>
                     MPTCP subflow information

       --tos  Show ToS and priority information. Below fields may appear:

              tos    IPv4 Type-of-Service byte

              tclass IPv6 Traffic Class byte

              class_id
                     Class id set by net_cls cgroup. If class is zero this shows priority set  by
                     SO_PRIORITY.

       --cgroup
              Show cgroup information. Below fields may appear:

              cgroup Cgroup  v2  pathname.  This  pathname  is relative to the mount point of the
                     hierarchy.

       --tipcinfo
              Show internal tipc socket information.

       -K, --kill
              Attempts  to  forcibly  close  sockets.  This  option  displays  sockets  that  are
              successfully  closed  and  silently  skips sockets that the kernel does not support
              closing. It supports IPv4 and IPv6 sockets only.

       -s, --summary
              Print summary statistics. This option does not parse socket lists obtaining summary
              from  various  sources. It is useful when amount of sockets is so huge that parsing
              /proc/net/tcp is painful.

       -E, --events
              Continually display sockets as they are destroyed

       -Z, --context
              As the -p option but also shows process security context. If the -T option is used,
              also shows thread security context.

              For netlink(7) sockets the initiating process context is displayed as follows:

                     1.  If valid pid show the process context.

                     2.  If destination is kernel (pid = 0) show kernel initial context.

                     3.  If a unique identifier has been allocated by the kernel or netlink user,
                         show context as "unavailable".  This  will  generally  indicate  that  a
                         process has more than one netlink socket active.

       -z, --contexts
              As  the  -Z  option  but also shows the socket context. The socket context is taken
              from the associated inode and is not the actual socket context held by the  kernel.
              Sockets are typically labeled with the context of the creating process, however the
              context shown will reflect any policy role,  type  and/or  range  transition  rules
              applied, and is therefore a useful reference.

       -N NSNAME, --net=NSNAME
              Switch to the specified network namespace name.

       -b, --bpf
              Show  socket  classic  BPF  filters  (only  administrators are allowed to get these
              information).

       -4, --ipv4
              Display only IP version 4 sockets (alias for -f inet).

       -6, --ipv6
              Display only IP version 6 sockets (alias for -f inet6).

       -0, --packet
              Display PACKET sockets (alias for -f link).

       -t, --tcp
              Display TCP sockets.

       -u, --udp
              Display UDP sockets.

       -d, --dccp
              Display DCCP sockets.

       -w, --raw
              Display RAW sockets.

       -x, --unix
              Display Unix domain sockets (alias for -f unix).

       -S, --sctp
              Display SCTP sockets.

       --tipc Display tipc sockets (alias for -f tipc).

       --vsock
              Display vsock sockets (alias for -f vsock).

       --xdp  Display XDP sockets (alias for -f xdp).

       -M, --mptcp
              Display MPTCP sockets.

       --inet-sockopt
              Display inet socket options.

       -f FAMILY, --family=FAMILY
              Display sockets of type FAMILY.  Currently the following  families  are  supported:
              unix, inet, inet6, link, netlink, vsock, tipc, xdp.

       -A QUERY, --query=QUERY, --socket=QUERY
              List  of  socket tables to dump, separated by commas. The following identifiers are
              understood:  all,  inet,  tcp,  udp,  raw,  unix,  packet,   netlink,   unix_dgram,
              unix_stream,   unix_seqpacket,   packet_raw,   packet_dgram,   dccp,   sctp,  tipc,
              vsock_stream, vsock_dgram, xdp, mptcp. Any item  in  the  list  may  optionally  be
              prefixed  by  an  exclamation  mark  (!)   to  exclude that socket table from being
              dumped.

       -D FILE, --diag=FILE
              Do not display anything, just dump raw information about TCP sockets to FILE  after
              applying filters. If FILE is - stdout is used.

       -F FILE, --filter=FILE
              Read  filter  information  from FILE.  Each line of FILE is interpreted like single
              command line option. If FILE is - stdin is used.

       --bpf-maps
              Pretty-print all the BPF socket-local data entries for each socket.

       --bpf-map-id=MAP_ID
              Pretty-print the BPF socket-local data entries for the requested  map  ID.  Can  be
              used more than once.

       FILTER := [ state STATE-FILTER ] [ EXPRESSION ]
              Please take a look at the official documentation for details regarding filters.

STATE-FILTER

       STATE-FILTER  allows  one  to  construct  arbitrary  set of states to match. Its syntax is
       sequence of keywords state and exclude followed by identifier of state.

       Available identifiers are:

              All standard TCP states: established, syn-sent, syn-recv,  fin-wait-1,  fin-wait-2,
              time-wait, closed, close-wait, last-ack, listening and closing.

              all - for all the states

              connected - all the states except for listening and closed

              synchronized - all the connected states except for syn-sent

              bucket - states, which are maintained as minisockets, i.e.  time-wait and syn-recv

              big - opposite to bucket

              bound-inactive  -  bound but otherwise inactive sockets (not listening, connecting,
              etc.)

EXPRESSION

       EXPRESSION allows filtering based on specific criteria.  EXPRESSION consists of  a  series
       of predicates combined by boolean operators. The possible operators in increasing order of
       precedence are or (or | or ||), and (or & or &&), and  not  (or  !).  If  no  operator  is
       between consecutive predicates, an implicit and operator is assumed. Subexpressions can be
       grouped with "(" and ")".

       The following predicates are supported:

       {dst|src} [=] HOST
              Test if the destination or source matches HOST. See HOST SYNTAX for details.

       {dport|sport} [OP] [FAMILY:]:PORT
              Compare the destination or source port to PORT. OP can be any of  "<",  "<=",  "=",
              "!=",  ">="  and  ">".  Following  normal  arithmetic rules. FAMILY and PORT are as
              described in HOST SYNTAX below.

       dev [=|!=] DEVICE
              Match based on the device the connection uses. DEVICE can either be a  device  name
              or the index of the interface.

       fwmark [=|!=] MASK
              Matches based on the fwmark value for the connection. This can either be a specific
              mark value or a mark value followed by a "/" and a bitmask of which bits to use  in
              the  comparison.  For  example  "fwmark  =  0x01/0x03" would match if the two least
              significant bits of the fwmark were 0x01.

       cgroup [=|!=] PATH
              Match if the connection is part of a cgroup at the given path.

       autobound
              Match if the port or path of the source address was automatically allocated (rather
              than explicitly specified).

       Most  operators  have  aliases.  If  no  operator is supplied "=" is assumed.  Each of the
       following groups of operators are all equivalent:

              • = == eq

              • != ne neq

              • > gt

              • < lt

              • >= ge geq

              • <= le leq

              • ! not

              • | || or

              • & && and

HOST SYNTAX

       The general host syntax is [FAMILY:]ADDRESS[:PORT].

       FAMILY must be one of the families supported by the -f option. If not given it defaults to
       the  family given with the -f option, and if that is also missing, will assume either inet
       or inet6. Note that all host conditions in the expression should either all  be  the  same
       family  or be only inet and inet6. If there is some other mixture of families, the results
       will probably be unexpected.

       The form of ADDRESS and PORT depends on the family used. "*" can be used as a wildcard for
       either the address or port. The details for each family are as follows:

       unix   ADDRESS  is a glob pattern (see fnmatch(3)) that will be matched case-insensitively
              against the unix socket's address. Both path and abstract names are supported. Unix
              addresses do not support a port, and "*" cannot be used as a wildcard.

       link   ADDRESS  is  the  case-insensitive  name  of an Ethernet protocol to match. PORT is
              either a device name or a device index for the desired link device, as seen in  the
              output of ip link.

       netlink
              ADDRESS  is  a  descriptor  of  the  netlink  family.  Possible  values  come  from
              /etc/iproute2/nl_protos. PORT is the port id of the socket, which  is  usually  the
              same  as  the  owning  process  id. The value "kernel" can be used to represent the
              kernel (port id of 0).

       vsock  ADDRESS is an integer representing the CID address, and PORT is the port.

       inet and inet6
              ADDRESS is an ip address (either v4 or  v6  depending  on  the  family)  or  a  DNS
              hostname  that  resolves  to an ip address of the required version. An ipv6 address
              must be enclosed in "[" and "]" to disambiguate the port separator. The address may
              additionally  have  a prefix length given in CIDR notation (a slash followed by the
              prefix length in bits). PORT is either the numerical socket port,  or  the  service
              name for the port to match.

USAGE EXAMPLES

       ss -t -a
              Display all TCP sockets.

       ss -t -a -Z
              Display all TCP sockets with process SELinux security contexts.

       ss -u -a
              Display all UDP sockets.

       ss -o state established '( dport = :ssh or sport = :ssh )'
              Display all established ssh connections.

       ss -x src /tmp/.X11-unix/*
              Find all local processes connected to X server.

       ss -o state fin-wait-1 '( sport = :http or sport = :https )' dst 193.233.7/24
              List all the tcp sockets in state FIN-WAIT-1 for our apache to network 193.233.7/24
              and look at their timers.

       ss -a -A 'all,!tcp'
              List sockets in all states from all socket tables but TCP.

SEE ALSO

       ip(8),
       RFC 793 - https://tools.ietf.org/rfc/rfc793.txt (TCP states)

AUTHOR

       ss was written by Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>.

       This manual page was written by Michael Prokop <mika@grml.org> for the Debian project (but
       may be used by others).

                                                                                            SS(8)