Help with 1720 routing issue

[Bullwinkle2009]

My mail server will not connect to mail.charter.net..

On my cisco router that interfaces with the T1, I can telnet to ib1.charter.net 25 without a problem (this is what the MX record points to).

On ANY machine beyond the cisco, it times out. My mail server is connected (through a switch) directly to the cisco, no firewall, etc. I cannot even ping ib1.charter.net from this side of the network.

BTW, ib1.charter.net (mail.charter.net) is the only domain I am having problems with. (that I know of anyway. we've been sending email to the rest of the world since the circuit has been installed (more than 3 years), with no problem).

My limited knowledge of cisco IOS is holding me up here. It appears that the router is not passing traffic to ib1 for whatever reason.

Thanks!

 

[North323]

post a scrubbed config

 

[Bullwinkle2009]

cisco#show config
Using 1173 out of 29688 bytes
!
version 12.0
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname cisco
!
enable secret 5 $1$N9tx$T5busU6fy8QfFDyqyu7kL0
enable password xxxxxxxx
!
!
!
!
!
memory-size iomem 25
ip subnet-zero
ip name-server 206.141.192.60
ip name-server 206.141.193.55
!
!
!
!
process-max-time 200
!
interface Serial0
ip unnumbered FastEthernet0
no ip directed-broadcast
encapsulation frame-relay IETF
no ip mroute-cache
service-module t1 timeslots 1-24
cdp enable
frame-relay lmi-type ansi
!
interface Serial0.672 point-to-point
description WAN
ip address 68.251.xxx.xxx 255.255.255.252
no ip directed-broadcast
frame-relay interface-dlci 672
!
interface FastEthernet0
ip address 68.253.xxx.xxx 255.255.255.128
no ip directed-broadcast
full-duplex
!
router igrp 1
redistribute connected
network 68.0.0.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 68.251.xxx.xxx
no ip http server
!
dialer-list 1 protocol ip permit
dialer-list 1 protocol ipx permit
snmp-server engineID local 0000000902000050547D42A3
snmp-server community public RO
!
line con 0
transport input none
line aux 0
line vty 0 4
password class
login
!
!
end

 

[North323]

can you ping 216.33.127.20 (ib1.charter.net) from inside the network?

 

[Bullwinkle2009]

No, I cannot ping that address from inside the network, but I can ping it from the router itself.

 

[North323]

are there access lists on the switch?

 

[Bullwinkle2009]

No, no access lists that I know of. It's a Synoptics 2803 (which is supposed to be pretty "dumb", just has the ability to partition, check stats, etc.).

 

[unclerico]

you need to detail your topology here. what device is providing NAT services to your inside network??

I hate all Uppercase... I don't want my groups to seem angry at me all the time! =)
- ColdFlame (vbscript forum)

 

[Bullwinkle2009]

There really is no NAT to the mail server, it has it's own static IP, and connects to a hub/dumb switch that is connected directly to the cisco 1720. Mail, Web, Name Servers, & 2 Firewalls (for internal office machines & wifi customers) connect to hub. Hub connects to Cisco Router. Cisco Router connects to T1 Smart Jack. I can make a drawing if needed...

I know nothing about the Cisco, except that I entered the syntax required to connect it to the T1. It was used, but fresh/clean/wiped when I bought it from a local vendor. Is there anything I can check to see if it is blocking this connection? I can't understand how anything else in the mix is causing a problem. I am going to try a different hub/switch or plug the mail server directly to the cisco to test in a little bit (once traffic dies down, though I can't understand how the hub has anything to do with it).

Thanks for the help so far. I do appreciate it!