Unable to reach certain IPs on the same subnet

Unanswered Question
Jul 8th, 2008

Hi,

I have a strange problem in hand for last few days. I am unable to reach few routers / servers on the same subnet. Ping, telnet, trace everything fails whereas few routers / servers respond and could able to connect from remote site.

As routers / servers which are not responding are critical, there is a service outage.

When I did a trace it stops at penultimate hop.

Src_LAN <IP-IP Tunnel> LAN <GRE tunnel> Destn_LAN {servers/routers}

I checked ARP, TCP MSS /MTU, etc etc ... no luck

I have also checked routing entries on all routers, no anomalies found.

DEBUG OUTPUT

UNSUCCESSFUL

=============

ATM_ROUTER#

telnet 10.200.161.202 /source-interface fa 0

Trying 10.200.161.202 ...

01:12:47: TCP: Random local port generated 40966, network 1

01:12:47: TCB83CEE050 created

01:12:47: TCB83CEE050 setting property TCP_TOS (11) 83FDE888

01:12:47: TCB83CEE050 bound to 10.180.15.41.40966

01:12:47: TCB83CEE050 setting property unknown (23) 83FDE7E8

01:12:47: Reserved port 40966 in Transport Port Agent for TCP IP type 1

01:12:47: TCP: sending SYN, seq 462969332, ack 0

01:12:47: TCP6: Connection to 10.200.161.202:23, advertising MSS 536

01:12:47: TCP6: state was CLOSED -> SYNSENT [40966 -> 10.200.161.202(23)]

01:12:49: TCP6: timeout #1 - timeout is 612 ms, seq 3036805087

01:12:49: cwnd from 536 to 536, ssthresh from 65535 to 1072

01:12:49: TCP6: timeout #1 - timeout is 4000 ms, seq 462969332

01:12:53: TCP6: timeout #2 - timeout is 8000 ms, seq 462969332

01:12:55: cwnd from 1483 to 536, ssthresh from 1072 to 1072

01:12:55: TCP6: timeout #1 - timeout is 610 ms, seq 3036806034

01:12:57: TCP7: timewait timeout timer expired

01:12:57: Released port 23 in Transport Port Agent for TCP IP type 1 delay 0

01:12:57: TCP7: state was TIMEWAIT -> CLOSED [23 -> 30.30.30.37(13890)]

01:12:57: TCB 0x831C99B8 destroyed

01:13:01: TCP6: timeout #3 - timeout is 15996 ms, seq 462969332

% Connection timed out; remote host not responding

ATM_ROUTER#

01:13:17: Released port 40966 in Transport Port Agent for TCP IP type 1 delay 240000

01:13:17: TCP6: state was SYNSENT -> CLOSED [40966 -> 10.200.161.202(23)]

01:13:17: TCB 0x83CEE050 destroyed

----

Successful

==========

ATM_ROUTER#telnet 10.180.161.248 /sour fa 0

Trying 10.180.161.248 ... Open

01:42:07: TCP: Random local port generated 42502, network 1

01:42:07: TCB831C99B8 created

01:42:07: TCB831C99B8 setting property TCP_TOS (11) 83FDE888

01:42:07: TCB831C99B8 bound to 10.200.15.41.42502

01:42:07: TCB831C99B8 setting property unknown (23) 83FDE7E8

01:42:07: Reserved port 42502 in Transport Port Agent for TCP IP type 1

01:42:07: TCP: sending SYN, seq 4213145868, ack 0

01:42:07: TCP6: Connection to 10.180.161.248:23, advertising MSS 536

01:42:07: TCP6: state was CLOSED -> SYNSENT [42502 -> 10.180.161.248(23)]

01:42:07: TCP6: Data repacketized, seq 1605308429, sent 28 byte

01:42:07: cwnd from 1922 to 536, ssthresh from 1072 to 1072

01:42:07: TCP6: timeout #1 - timeout is 606 ms, seq 1605308429

01:42:07: TCP6: state was SYNSENT -> ESTAB [42502 -> 10.180.161.248(23)]

01:42:07: TCP: tcb 831C99B8 connection to 10.180.161.248:23, peer MSS 536, MSS is 536

01:42:07: TCB831C99B8 connected to 10.180.161.248.23

User Access Verification

Username: cisco

01:42:09: TCP6: ACK timeout timer expired

Password: xxxxx

01:42:11: TCP6: ACK timeout timer expired

DESTN_ROUTER>

DSTN_RA>trace 10.200.15.41 (ATM RTR)

Type escape sequence to abort.

Tracing the route to 10.200.15.41

1 10.180.161.251 4 msec 4 msec 0 msec

2 192.168.70.222 560 msec 576 msec 564 msec

3 10.180.196.240 700 msec 500 msec 552 msec

4 30.30.30.38 892 msec 1040 msec 1780 msec

DSTN_RB>trace 10.200.15.41

Type escape sequence to abort.

Tracing the route to 10.200.15.41

1 10.180.161.251 4 msec 0 msec 0 msec

2 192.168.70.222 752 msec 696 msec 676 msec

3 10.180.196.240 1172 msec 792 msec 668 msec

4 * * *

5 * * *

6

Rgds,

VJ

I have this problem too.
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letsgomets Tue, 07/08/2008 - 10:58

Have you looked at this device?

30.30.30.38 892

The problem may be on that guy. Not sure which device is the ATM_Router

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