Provided by: iproute2_6.1.0-1ubuntu6_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.

       -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).

       -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.  -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.

              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

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)