2801 problem, weird

[mikeleahy]

Hi

i have two 2801s connected via serial cable to isp cloud etc. The link is fine and pcs can open apps over the link no problem. I can ping servers in cork and dublin for each site from a pc or server, but when i use telnet to the router and try and ping a server it times out on both routers. the routers can ping each other but not servers!!!!! why would this happen, obviouslt the pc traffic is being routed through the router and it is passed, also our phone company converts the voice to lan traffic and this dosent seem to be getting through either... i have not configured any access list or rules on any interface??

 

[MartinR82]

try pinging with the DF bit set, if this fails then you know that the carrier does not allow packets with the DF bit set to 1 and the way around this is to setup a GRE tunnel between the routers as GRE traffic has the DF bit set to 0 by default and then all in tunnel traffic can have the DF bit set to 1 and the carrier wont see it.

 

[JOAMON]

Can you post both router configs?

 

[mikeleahy]

the ping works using the df bit set. what does this mean???

 

[mikeleahy]

sorry, it pings when i use extended ping and say yes to dont fragment and enter the source address... if i dont enter the source addresss it fails. will i turn off the fragmentataion in the config. if so how do i do this

 

[plshlpme]

what if you try to do a trace to this server that you cannot ping?
it would tell you if you have an acl of some sort blocking access from your wan interface.. what interface were you sourcing your ping from to make it work? the lan interface?

 

[mikeleahy]

the trace goes out on the leased line and just times out after the second hop. if i do a trace from a pc or serve than the trace goes all the way into the other lan. i cant understand this. yes i was sourcing from the lan int to make it work

 

[plshlpme]

so is your wan subnet being filtered somewhere along the way?
if you trace to the server from the router and source it off the lan does it work?

just for clarification when you say you have two 2801's conencted via serial cable... is it like this?

2801 --- ISP ---2801 ?

do you have any acls attached inbound on your serial links?

 

[mikeleahy]

i dont know if the wan subnet is being filtered, how do i find out this. the only acl on the router is the default sdm that i cant get rid of,

2801 - - isp --- 2801 is correct

when i try to source it off the lan it says you must use the full ip address and wont even recognise a lan address. it only works with its own address 192.168.1.7

 

[JOAMON]

plshlpme..

You can view his configs in a previous post.

http://www.tek-tips.com/viewthread.cfm?qid=1202773

Take a look and see what you think.

What I note is that he has multilink interface setup with only one serial interface in it. Not needed. Also I see some type of compression setup for voice in the multilink interface. This may be causing some problems as well. He changed the CORK config and added the internal subnet into his RIP statement but the internal LAN is not in the DUBLIN RIP statement. He may need at add ip routes like:
Cork router
ip route 192.168.0.0 255.255.255.0 159.134.142.166
Dublin router
ip route 192.168.1.0 255.255.255.0 159.134.61.182

 

[mikeleahy]

adding those routes wont help i think, those routes are alreayd there i.e. in cork 192.168.1.0 255.255.255.0 serial 0/1/0 and vice versa in dublin
.

as you say i dont have the internal subnet in dublin, should i remove it from cork or add it to dublin do you think.....

the compression is a recommendation to fragment large packets. i dont really understand what its doing

 

[JOAMON]

Those static routes would help if as you say RIP statements are not being advertised correctly. Can you post the output of "show ip route" form each router? The output from "show cdp neighbors detail" of each router might also be helpful.

 

[mikeleahy]

i am on hols for the next few days, i wll reply with the info then. the sh ip route shows the proper routes though.
thanks for your help so far

 

[plshlpme]

well if it was me... i would lose the rip, multilink, routemap and go from there

u have a /24 on each side.. so one static route in each router would do the trick for that.

you mention the telco converts your voice to data...
is that via a mux? and part of the 512k line? where is that done? or is it just voip from a pbx?

 

[mikeleahy]

it is just voip from a pbx. and it sent over the leased line as data. why would this not be going over???

 

[plshlpme]

first glance i would suspect your routmap

have you tried removing the route map and null0 static routes?

 

[mikeleahy]

not yet, will i remove the route map and the multilink. you say to remove the rip, i cannot do that as i need to receive the isp's routing info using rip version 2.. how else will the router get the routing tables.... if i just have the basic ethernet and serial configured, and the rip and static route. should i do the static route as

ip route 'destination subnet' mask and next hop (serial 0/1/0)

or

ip route 'destination subnet' mask and next hop (ip address of serial interface

 

[JOAMON]

would you please post the output from both routers of "show ip route"

 

[mikeleahy]

her is cork

Gateway of last resort is 0.0.0.0 to network 0.0.0.0

159.134.0.0/16 is variably subnetted, 4 subnets, 2 masks
R 159.134.142.166/32 [120/1] via 159.134.61.181, 00:00:05, Multilink1
R 159.134.142.164/30 [120/1] via 159.134.61.181, 00:00:05, Multilink1
C 159.134.61.180/30 is directly connected, Multilink1
C 159.134.61.181/32 is directly connected, Multilink1
R 192.168.0.0/24 [120/2] via 159.134.61.181, 00:00:05, Multilink1
C 192.168.1.0/24 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 is directly connected, Serial0/1/0

dublin is
Gateway of last resort is 0.0.0.0 to network 0.0.0.0

159.134.0.0/16 is variably subnetted, 4 subnets, 2 masks
C 159.134.142.165/32 is directly connected, Multilink1
C 159.134.142.164/30 is directly connected, Multilink1
is directly connected, Serial0/1/0
R 159.134.61.180/30 [120/1] via 159.134.142.165, 00:00:11, Multilink1
R 159.134.61.182/32 [120/1] via 159.134.142.165, 00:00:11, Multilink1
C 192.168.0.0/24 is directly connected, FastEthernet0/0
R 192.168.1.0/24 [120/2] via 159.134.142.165, 00:00:11, Multilink1
S* 0.0.0.0/0 is directly connected, Serial0/1/0

 

[mikeleahy]

the sh cdp nei detail from dublin givees

Device ID: edge6-cwm
Entry address(es):
IP address: 159.134.142.165
Platform: cisco 7206VXR, Capabilities: Router
Interface: Multilink1, Port ID (outgoing port): Multilink1
Holdtime : 128 sec

Version :
Cisco Internetwork Operating System Software
IOS (tm) 7200 Software (C7200-P-M), Version 12.3(9c), RELEASE SOFTWARE (fc2)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Tue 30-Nov-04 19:21 by kellythw

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from cork its

Device ID: edge2-qkr
Entry address(es):
IP address: 159.134.61.181
Platform: cisco 7206VXR, Capabilities: Router
Interface: Multilink1, Port ID (outgoing port): Multilink5
Holdtime : 151 sec

Version :
Cisco Internetwork Operating System Software
IOS (tm) 7200 Software (C7200-P-M), Version 12.3(9c), RELEASE SOFTWARE (fc2)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Tue 30-Nov-04 19:21 by kellythw

advertisement version: 2