Cannot Telnet or SSH on WAN port cisco 892

[sudan_023]

Hey guys,

                 I cannot telnet or ssh on WAN port ge0 on my cisco 892. There is no any access-list for the vty access. please help me out here is the output of #debug ip tcp transactions.

A.A.A.A : cisco 892 public ip on ge0 port

X.X.X.X : remote ip

#debug ip tcp transactions

*Apr  1 06:24:24.791: Reserved port 0 in Transport Port Agent for TCP IP type 0
*Apr  1 06:24:24.791: Released port 0 in Transport Port Agent for TCP IP type 0 delay 240000
*Apr  1 06:24:24.791: Reserved port 23 in Transport Port Agent for TCP IP type 1
*Apr  1 06:24:24.791: TCP0: state was LISTEN -> SYNRCVD [23 -> X.X.X.X(56834)]
*Apr  1 06:24:24.791: TCP: tcb 861895B4 connection to X.X.X.X:56834, peer MSS 536, MSS is 516
*Apr  1 06:24:24.791: TCP: sending SYN, seq 1787056797, ack 2033464572
*Apr  1 06:24:24.791: TCP0: Connection to X.X.X.X:56834, advertising MSS 536
*Apr  1 06:24:24.835: TCP0: RST received, Closing connection
*Apr  1 06:24:24.835: TCP0: state was SYNRCVD -> CLOSED [23 -> X.X.X.X(56834)]
*Apr  1 06:24:24.835: tcp0: T CLOSED X.X.X.X:56834 A.A.A.A:23 early close
*Apr  1 06:24:24.835: Released port 23 in Transport Port Agent for TCP IP type 1 delay 240000
*Apr  1 06:24:24.835: TCB 0x861895B4 destroyed
*Apr  1 06:24:26.763: Reserved port 0 in Transport Port Agent for TCP IP type 0
*Apr  1 06:24:26.763: Released port 0 in Transport Port Agent for TCP IP type 0 delay 240000
*Apr  1 06:24:26.763: Reserved port 23 in Transport Port Agent for TCP IP type 1
*Apr  1 06:24:26.763: TCP0: state was LISTEN -> SYNRCVD [23 -> X.X.X.X(56834)]
*Apr  1 06:24:26.763: TCP: tcb 861895B4 connection to X.X.X.X:56834, peer MSS 536, MSS is 516
*Apr  1 06:24:26.767: TCP: sending SYN, seq 3836467071, ack 2033464572
*Apr  1 06:24:26.767: TCP0: Connection to X.X.X.X:56834, advertising MSS 536
*Apr  1 06:24:26.779: TCP0: RST received, Closing connection
*Apr  1 06:24:26.779: TCP0: state was SYNRCVD -> CLOSED [23 -> X.X.X.X(56834)]
*Apr  1 06:24:26.779: tcp0: T CLOSED X.X.X.X:56834 A.A.A.A:23 early close
*Apr  1 06:24:26.779: Released port 23 in Transport Port Agent for TCP IP type 1 delay 240000
*Apr  1 06:24:26.779: TCB 0x861895B4 destroyed
*Apr  1 06:24:30.775: Reserved port 0 in Transport Port Agent for TCP IP type 0
*Apr  1 06:24:30.775: Released port 0 in Transport Port Agent for TCP IP type 0 delay 240000
*Apr  1 06:24:30.775: Reserved port 23 in Transport Port Agent for TCP IP type 1
*Apr  1 06:24:30.775: TCP0: state was LISTEN -> SYNRCVD [23 -> X.X.X.X(56834)]
*Apr  1 06:24:30.775: TCP: tcb 861895B4 connection to X.X.X.X:56834, peer MSS 536, MSS is 516
*Apr  1 06:24:30.775: TCP: sending SYN, seq 242584546, ack 2033464572
*Apr  1 06:24:30.775: TCP0: Connection to X.X.X.X:56834, advertising MSS 536
*Apr  1 06:24:30.791: TCP0: RST received, Closing connection
*Apr  1 06:24:30.791: TCP0: state was SYNRCVD -> CLOSED [23 -> X.X.X.X(56834)]
*Apr  1 06:24:30.791: tcp0: T CLOSED X.X.X.X:56834 A.A.A.A:23 early close
*Apr  1 06:24:30.791: Released port 23 in Transport Port Agent for TCP IP type 1 delay 240000
*Apr  1 06:24:30.791: TCB 0x861895B4 destroyed
*Apr  1 06:24:38.807: Reserved port 0 in Transport Port Agent for TCP IP type 0
*Apr  1 06:24:38.807: Released port 0 in Transport Port Agent for TCP IP type 0 delay 240000
*Apr  1 06:24:38.807: Reserved port 23 in Transport Port Agent for TCP IP type 1
*Apr  1 06:24:38.807: TCP0: state was LISTEN -> SYNRCVD [23 -> X.X.X.X(56834)]
*Apr  1 06:24:38.807: TCP: tcb 861895B4 connection to X.X.X.X:56834, peer MSS 536, MSS is 516
*Apr  1 06:24:38.807: TCP: sending SYN, seq 463060989, ack 2033464572
*Apr  1 06:24:38.807: TCP0: Connection to X.X.X.X:56834, advertising MSS 536
*Apr  1 06:24:38.823: TCP0: RST received, Closing connection
*Apr  1 06:24:38.823: TCP0: state was SYNRCVD -> CLOSED [23 -> X.X.X.X(56834)]
*Apr  1 06:24:38.823: tcp0: T CLOSED X.X.X.XA.A.A.A:56834 A.A.A.A:23 early close
*Apr  1 06:24:38.823: Released port 23 in Transport Port Agent for TCP IP type 1 delay 240000
*Apr  1 06:24:38.823: TCB 0x861895B4 destroyedX.X.X.X

[andamani]

Hi,

Could you please paste the following output:

sh run | sec aaa

sh run | b line.

Regards,

Anisha

P.S.: please mark this thread as answered if you feel your query is resolved. Do rate helpful posts.

[paolo bevilacqua · Accepted solution]

Please post NAT config including relevant ACL.

[pcfreak49]

hello sudan we have access-class vty in line?

[Richard Burts]

Several of my colleagues have requested additional information. And that additional information may be helpful. But I will try to start an explanation based on the debug output that you posted. The debug output shows a series of events that repeat over and over:

- the router receives a TCP SYN request on TCP 23 (the telnet port).

- the router sends a SYN/ACK in response (which is standard TCP protocol behavior).

- the router receives a RST (which is a reset and has the effect of terminating immediately the budding TCP session.

- the router tears down the resources allocated for this connection.

From this I believe that we can say that the problem is not a problem with basic IP connectivity. (the request for telnet is getting to the router). And I believe that we can say that the problem is not an access list (not an access group on an interface or an access class on the vty lines). If it were an access list issue then the router would not send the SYN/ACK.

I wonder if there might be some firewall or some IPS system examining the traffic and sending the reset.

In the mean time please do send the additional information requested by my colleagues. Perhaps we may get some insight from it into what the problem is.

HTH

Rick

[sudan_023]

thank you guys it was NAT ACL doing all these things   thank you for your support.

[pcfreak49]

happy to hear that's done sudan

[paolo bevilacqua]

Thanks for the nice rating and good luck!