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New Member

CISCO 2501 IGRP HELP

I HAVE 2 CISCO ROUTER 2501.

I NEED TO CONFIG IGRP AND I HAVE PROBLEM

ROUTER A:

E0 IP 192.168.2.8 -> FOR NETWORK 192.168.2.0

S0 IP 192.168.10.2

ROUTER IGRP 1

NETWORK 192.168.4.0

NETWORK 192.168.10.0

ROUTER B:

E0 IP 192.168.4.1

S0 IP 192.168.10.1

ROUTER IGRP 1

NETWORK 192.168.2.0

NETWORK 192.168.10.0

NOW WHEN I SHOW IP ROUTE

IN ROUTER B I SEE IGRP WORKING FOLLOWING,

I 192.168.2.0/24 ROUTING VIA 192.168.10.2 SERIAL 0

LATER

I SEE

I 192.168.2.0/24 IS POSSIBLE DOWN, ROUTING VIA 192.168.10.2, SERIAL 0

AND

ROUTER A I DO NOT SEE IGRP WORKING AT ALL

CAN ANYONE HELP ME WHAT DID I DO WRONG.

THANKS A LOT

TOM

18 REPLIES
Bronze

Re: CISCO 2501 IGRP HELP

Hi Tom,

try reversing the network statements, so

ROUTER A:

ROUTER IGRP 1

NETWORK 192.168.2.0

NETWORK 192.168.10.0

ROUTER B:

ROUTER IGRP 1

NETWORK 192.168.4.0

NETWORK 192.168.10.0

hth

Herbert

New Member

Re: CISCO 2501 IGRP HELP

Thanks Herbert,

It is working now.

I have another question if you could solve it for me

Now in my win2k server 192.168.2.0 network and gateway is 192.168.2.8 for Router A. I cannot ping to network 192.168.4.0 in win2k server.

In win2k server I have two gateway 192.168.2.2 point to cable router and 192.168.2.8 point to Router A.

but In router A there. I can ping to network 192.168.4.0.

Do you know why ? thanks for your helps

New Member

Re: CISCO 2501 IGRP HELP

On your Win2K server, make RouterA as the first preferred gateway.Also check if the subnet mask on the server and RouterA matches.

New Member

Re: CISCO 2501 IGRP HELP

Thanks for your idea. thanks again.

If I put 192.168.2.8 as prefer gateway first and 192.168.2.2 as my cable router. I still can not ping to router b 192.168.4.0 network and I cannot get to internet in win2k server. If I put 192.168.2.2 as prefer gateway 1st place then 192.168.2.8 . this time I can go to internet but I still cannot ping to 192.168.4.0 network

do you know why here?

If you have time you can give me some feeback here.thanks

Bronze

Re: CISCO 2501 IGRP HELP

You cannot have 2 default gateways on your server.

There are 2 solutions:

1/ you remove the default gw 192.168.2.8 and you define a static route to 192.168.4.0 on your server:

route ADD 192.168.4.0 MASK 255.255.255.0 192.168.2.8

2/ you remove the default gw 192.168.2.2 on the server and you add a default route on routerA:

ip route 0.0.0.0 0.0.0.0 192.168.2.2

The advantage of option 2 is that the config of the server stays simple (well, most people don't like adding routes on servers, and I agree). Also, in this case network 192.68.4.0 will also be able to access the internet; provided that your cable router does NAT for this range as well, and your router B needs a default route to router A (either static or received from A in IGRP).

hth

Herbert

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, Thanks a lot.

you gave some usefull tips her.

I just so glad you can point me these options.

thanks again.

New Member

Re: CISCO 2501 IGRP HELP

Hebert, since win2k server default gateway 192.168.2.8 router A and all network 192.168.2.0 can access to internet.

Now Router B can not access to internet.

Both router has IGRP running.

You said router B is either static or received from

router A in IGRP.

why router B cannot access to internet.

Do I need to add default route 0.0.0.0 0.0.0.0 192.168.2.8 in router B

can you help me ? thanks

Bronze

Re: CISCO 2501 IGRP HELP

Yes, as I said router B needs a default route. You can achieve this in 2 ways:

1/ you add a static default route on router B

ip route 0.0.0.0 0.0.0.0 serial0

OR

2/ you make router A announce a default route in IGRP, e.g. by redistributing (all) its static routes:

router igrp x

redistribute static

Note that if router A has static routes that you do not want router B to learn, you can add a distribute-list:

access-list 1 permit 0.0.0.0

access-list 1 permit 192.168.2.0

router igrp

distribute-list 1 out

hth

Herbert

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert,

Sorry, I did not see this reply until now.

again thanks for your input

thanks

Tom

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, I hate to bother you again.

since I follow your opinion that I choose option 1 to add static route to serial0 in router B then

I try to ping yahoo.com. there is not respond.

Router A has default route to 192.168.2.2 as cable internet router

Do you know why?

Router A has serial0 DTE cable to connect to Router B DCE serial0

thanks

Bronze

Re: CISCO 2501 IGRP HELP

It seems that I overlooked something last time.

All your routing is ok now, except on the cable router: it does not know how to reach the network behind router B.

So: add a static route on your cablerouter to 192.168.4.0/24 with router A as next-hop.

That should do it.

regards

Herbert

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, Thanks again for input.

You are right. I had a feeling too that cable router not know how to reach router B.

but unfortunely I have SMC cable router with basic routing scheme that do not allow me add static route to it.

Is that true I can go no where for router B? unless I get some kind real router.

thanks

Bronze

Re: CISCO 2501 IGRP HELP

Hi again,

you might get away with it by using proxy arp, but you may find it a bit tricky though.

This document describes how to do it:

http://www.cisco.com/en/US/customer/tech/tk648/tk361/technologies_tech_note09186a0080094adb.shtml

Just imagine that host A is your cable router, and the router is your router A.

Basically it comes down to 2 modifications:

1/ change the subnet mask on the cable router's ethernet interface to 255.255.0.0

This will make it send ARP requests for all hosts in 192.168.x.x (including lan B).

2/ enable proxy arp on router A's ethernet interface; this will make the router respond to arp requests for addresses on lan B, so the cablerouter will send packets destined for lan B to router A; router A then forwards them to router B as normal.

Note that step 1 will cause some extra arp traffic on lan A, but if there are not too many hosts on lan B and the arp cache timeout on the cablerouter is not too low, this should not be a problem.

hth

Herbert

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, thanks for thoughtfull with this ideas.

I will try it again.

tom

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, You sent me this link that it requires cisco login and password. I have registered cisco login and password but it will not allow me to view this page. Would that be you have authorized to login this technical stuff from cisco. not for me as normal registered forum users.

http://www.cisco.com/en/US/customer/tech/tk648/tk361/technologies_tech_note09186a0080094adb.shtml

thanks

Tom wu

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, never mind I found it.

thanks again.

New Member

Re: CISCO 2501 IGRP HELP

Hi Herbert, I am using 2 cisco 2500 router

2 serials port and aui ports

thanks

Bronze

Re: CISCO 2501 IGRP HELP

Just add the following static route to router B

ip route 0.0.0.0 0.0.0.0 192.168.2.2

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