debug ip tcp

Displays debugging information about Transmission Control Protocol (TCP) transactions.
Syntax
debug ip tcp [ adjust-mss | ao | close | driver | memory |packet | sack | status | transactions | vrf ] { ipv4-address | ipv6-address }
no debug ip tcp [ adjust-mss | ao | close | driver | memory | packet | sack | status | transactions | vrf ] { ipv4-address | ipv6-address }
Parameters
adjust-mss
Specifies IPv4 TCP MSS.
ao
Specifies TCP keychain authentication (AO) options.
close
Specifies TCP close events.
driver
Specifies TCP driver events.
memory
Specifies TCP memory usage.
packet
Specifies TCP packets.
sack
Specifies TCP Selective-Acknowledgment (SACK).
status
Specifies the status of TCP connections.
transactions
Specifies significant TCP events.
vrf
Specifies VRF-based TCP.
ipv4-address
Specifies an IPv4 address.
ipv6-address
Specifies an IPv6 address.
Modes

Privileged EXEC mode

Usage Guidelines

The no form of the command disables TCP debugging options.

Examples

The following example displays debugging information about TCP transactions.

device# debug ip tcp 2001:DB8::192:111:101:25
TCP: ipv6 address 2001:DB8::192:111:101:25 debugging is on
Debug: Feb 11 10:46:57 TCP: sent packet (len=41) 2001:DB8::192:111:101:111:8197 ->
2001:DB8::192:111:101:25:179
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:18c2,seqn:11211247,ackn:835929143
Debug: Feb 11 10:46:57 TCP: sent packet (len=41) 2001:DB8::192:111:101:111:8197 ->
2001:DB8::192:111:101:25:179
packet:
syn:0,ack:1,rst:0,fin:1,hlen:5,chksum:14ac,seqn:11211268,ackn:835929143
Debug: Feb 11 10:46:57 TCP: rcvd packet (len=20) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8197
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:3bfa,seqn:835929143,ackn:11211268
Debug: Feb 11 10:46:57 TCP: rcvd packet (len=20) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8197
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:3bf9,seqn:835929143,ackn:11211290
Debug: Feb 11 10:46:57 TCP: rcvd packet (len=20) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8197
packet:
syn:0,ack:1,rst:0,fin:1,hlen:5,chksum:3bce,seqn:835929143,ackn:11211290
Debug: Feb 11 10:46:57 TCP: sent packet (len=20) 2001:DB8::192:111:101:111:8197 ->
2001:DB8::192:111:101:25:179
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:1bce,seqn:11211290,ackn:835929144
Debug: Feb 11 10:47:05 TCP: sent packet (len=24) 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179
packet: syn:1,ack:0,rst:0,fin:0,hlen:6,chksum:26f,seqn:4002716695,ackn:0
Debug: Feb 11 10:47:05 TCP: rcvd packet (len=24) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8178
packet:
syn:1,ack:1,rst:0,fin:0,hlen:6,chksum:17a4,seqn:2607451983,ackn:4002716696
Debug: Feb 11 10:47:05 TCP: sent packet (len=20) 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:ef48,seqn:4002716696,ackn:2607451984
Debug: Feb 11 10:47:05 TCP: sent packet (len=75) 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:17de,seqn:4002716696,ackn:2607451984
Debug: Feb 11 10:47:05 TCP: rcvd packet (len=20) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8178
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:2f49,seqn:2607451984,ackn:4002716751
Debug: Feb 11 10:47:05 TCP: rcvd packet (len=57) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8178
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:fc84,seqn:2607451984,ackn:4002716751
Debug: Feb 11 10:47:05 TCP: sent packet (len=20) 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:ef11,seqn:4002716751,ackn:2607452021
Debug: Feb 11 10:47:05 TCP: rcvd packet (len=39) 2001:DB8::192:111:101:25:179 ->
2001:DB8::192:111:101:111:8178
packet:
syn:0,ack:1,rst:0,fin:0,hlen:5,chksum:cd4a,seqn:2607452235,ackn:4002716770
Debug: Feb 11 10:47:06 TCP: sent packet (len=20) 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:17

The following example activates TCP driver events debugging.

device# debug ip tcp driver
TCP: driver debugging is on

The following example activates TCP memory debugging.

device# debug ip tcp memory
TCP: memory debugging is on

The following example activates TCP packets debugging.

device# debug ip tcp packet
TCP: packet debugging is on

The following example activates TCP SACK debugging.

device# debug ip tcp sack
TCP: sack debugging is on

The following example displays details for TCP transactions debugging.

device# debug ip tcp transactions
TCP: transactions debugging is on
TCP: transactions debugging is on
Debug: Feb 11 10:47:39 TCP: 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179: state change ESTABLISHED -> FIN-WAIT-1
Debug: Feb 11 10:47:39 TCP: sending FIN to 2001:DB8::192:111:101:25 port 179
Debug: Feb 11 10:47:39 TCP: FIN to 2001:DB8::192:111:101:111 port 8178 acked
Debug: Feb 11 10:47:39 TCP: 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179: state change FIN-WAIT-1 -> FIN-WAIT-2
Debug: Feb 11 10:47:39 TCP: 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179: state change FIN-WAIT-2 -> TIME-WAIT
Debug: Feb 11 10:47:39 TCP: FIN processed
Debug: Feb 11 10:47:39 TCP: 2001:DB8::192:111:101:111:8178 ->
2001:DB8::192:111:101:25:179: state change TIME-WAIT -> CLOSED
Debug: Feb 11 10:47:39 TCP: TCB 14440934 destroyed
Debug: Feb 11 10:47:58 TCP: 2001:DB8::192:111:101:111:8064 ->
2001:DB8::192:111:101:25:179: state change CLOSED -> SYN-SENT
Debug: Feb 11 10:47:58 TCP: connected to 2001:DB8::192:111:101:111 port 8064
advertising MSS 1436
Debug: Feb 11 10:47:58 TCP: connection to 10.146.1.17 port 179 received MSS 1436
MSS is 1436
Debug: Feb 11 10:47:58 TCP: 2001:DB8::192:111:101:111:8064 ->
2001:DB8::192:111:101:25:179: state change SYN-SENT -> ESTABLISHED
The following example debugs TCP keychain authentication (AO) options.
device# debug ip tcp ao                                
          TCP:  ao debugging is on
The following example displays TCP status debugging information for the specified IP addresses.
device# debug ip tcp status 17.1.1.2 8003 17.1.1.1 179 
TCP: TCB = 0xa4138b3b 
TCP: 17.1.1.2:8003 <-> 17.1.1.1:179: state: ESTABLISHED 
  Send: initial sequence number = 17564913 
  Send: first unacknowledged sequence number = 17883929 
  Send: current send pointer = 17883929 
  Send: next sequence number to send = 17883929 
  Send: remote received window = 16365 
  Send: total unacknowledged sequence number = 0 
  Send: last window update sequence number = 154132788 
  Send: last window update ack number = 17883929 
  Send: need to send ack = 0, probe = 0
  Send: total used buffers 0 
  Receive: initial incoming sequence number = 153787685 
  Receive: expected incoming sequence number = 154132788 
  Receive: received window = 16384 
  Receive: bytes in receive queue = 0 
  Receive: congestion window = 1439 
    TCP Connection state: ESTABLISHED, timer state 0
     TCP Keychain name      : 1
     TCP-AO Enabled         : YES
     TCP-AO in use          : YES
     Keychain valid         : YES
     No of segments dropped : 0
     Send-Active-Key
     ---------------
       Key-id               : 1                                   
       Crypto Algorithm     : AES-128-CMAC
       Send-id              : 100
       Recv-id              : 100
       Include-tcp-options  : YES
       Accept-ao-mismatch   : YES
     Recv-Active-Key
     ---------------
       Key-id               : 1
       Crypto Algorithm     : AES-128-CMAC
       Send-id              : 100
       Recv-id              : 100
       Include-tcp-options  : YES
       Accept-ao-mismatch   : YES

       Maximum segment size: 1420
       Local host:  17.1.1.2, Local  Port: 8003
       Remote host: 17.1.1.1, Remote Port: 179
       ISentSeq:   17564913  SendNext:   17883929  TotUnAck:          0
       TotSent:      319016  ReTrans:          40  UnAckSeq:   17883929
       SeqLastWin:   154132788  AckLastWin:    17883929  SendAck: 0
       IRcvSeq:   153787685  RcvNext:   154132788  SendWnd:       16365
       TotalRcv:     345103  DupliRcv:       1083  RcvWnd:        16384
       SendQue:           0  RcvQue:            0  CngstWnd:       1439
The following example displays TCP debugging information for the specified VRF and IP addresses.
device# debug ip tcp vrf blue status 15.1.1.2 179 15.1.1.1 8220 
TCP: TCB = 0xa413abd5 
TCP: 15.1.1.2:179 <-> 15.1.1.1:8220: state: ESTABLISHED 
  Send: initial sequence number = 21517275 
  Send: first unacknowledged sequence number = 21836345 
  Send: current send pointer = 21836345 
  Send: next sequence number to send = 21836345 
  Send: remote received window = 16365 
  Send: total unacknowledged sequence number = 0 
  Send: last window update sequence number = 155899645 
  Send: last window update ack number = 21836345 
  Send: need to send ack = 0, probe = 0
  Send: total used buffers 0 
  Receive: initial incoming sequence number = 155554412 
  Receive: expected incoming sequence number = 155899645 
  Receive: received window = 16384 
  Receive: bytes in receive queue = 0 
  Receive: congestion window = 3017 
    TCP Connection state: ESTABLISHED, timer state 0
     TCP Keychain name      : 1
     TCP-AO Enabled         : YES
     TCP-AO in use          : YES
     Keychain valid         : YES
     No of segments dropped : 0
     Send-Active-Key
     ---------------
       Key-id               : 1                                   
       Crypto Algorithm     : AES-128-CMAC
       Send-id              : 100
       Recv-id              : 100
       Include-tcp-options  : YES
       Accept-ao-mismatch   : YES
     Recv-Active-Key
     ---------------
       Key-id               : 1
       Crypto Algorithm     : AES-128-CMAC
       Send-id              : 100
       Recv-id              : 100
       Include-tcp-options  : YES
       Accept-ao-mismatch   : YES

       Maximum segment size: 1420
       Local host:  15.1.1.2, Local  Port: 179
       Remote host: 15.1.1.1, Remote Port: 8220
       ISentSeq:   21517275  SendNext:   21836345  TotUnAck:          0
       TotSent:      319070  ReTrans:           0  UnAckSeq:   21836345
       SeqLastWin:   155899645  AckLastWin:    21836345  SendAck: 0
       IRcvSeq:   155554412  RcvNext:   155899645  SendWnd:       16365
       TotalRcv:     345233  DupliRcv:          0  RcvWnd:        16384
       SendQue:           0  RcvQue:            0  CngstWnd:       3017
History
Release version Command history
09.0.10 This command was modified to add TCP keychain authentication (AO) option debugging.