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New Member

Unable to reach certain IPs on the same subnet

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

2 REPLIES

Re: Unable to reach certain IPs on the same subnet

show the configurations

New Member

Re: Unable to reach certain IPs on the same subnet

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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