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New Member

changing the default gateway

I've got a router where I change the default gateway, but when I do a traceroute the connection still goes through the old gateway. Is there a command I'm missing that tells the router to use the new one?

15 REPLIES
New Member

Re: changing the default gateway

Did you remove the old route?

New Member

Re: changing the default gateway

Yes, I did.

New Member

Re: changing the default gateway

Make sure you don't use the "default-gateway" configuration directive. Use "route 0.0.0.0".

default-gateway only pertains to routers with "no ip routing".

Mick.

New Member

Re: changing the default gateway

Here was the old part of the config:

ip default-gateway 192.168.168.9

ip classless

ip route 0.0.0.0 0.0.0.0 192.168.168.9

no ip http server

and here is the new:

ip default-gateway 192.168.168.88

ip classless

ip route 0.0.0.0 0.0.0.0 192.168.168.88

no ip http server

That's all I changed, but it appears that it's still going through the .9 address when I traceroute.

The .9 router is at one location on our WAN and the .88 is at another.

New Member

Re: changing the default gateway

any policy routing?

do a show ip route x.x.x.x (the address you're doing the tracert to) and a show ip route 192.168.168.88

from this router.

Mick.

New Member

Re: changing the default gateway

Here it is:

WestVirgina1750#show ip route 192.168.168.88

Routing entry for 192.168.168.0/24

Known via "eigrp 7000", distance 90, metric 20514560, type internal

Redistributing via eigrp 7000

Last update from 192.168.168.9 on Serial0.30, 2w0d ago

Routing Descriptor Blocks:

* 192.168.168.9, from 192.168.168.9, 2w0d ago, via Serial0.30

Route metric is 20514560, traffic share count is 1

Total delay is 20100 microseconds, minimum bandwidth is 128 Kbit

Reliability 255/255, minimum MTU 1500 bytes

Loading 1/255, Hops 1

The one I'm trying to get to does not work. It's a public address outside the WAN.

New Member

Re: changing the default gateway

If the old route is still live and the metric is lower, its going to take the old route. whack the admin distance

New Member

Re: changing the default gateway

What does whack the admin distance mean?

The old route is still live and the metric is the same.

New Member

Re: changing the default gateway

Make sure you remove the "Default gateway" command...do a "Clear ip route" and give it another try.

New Member

Re: changing the default gateway

Nothing. I do a show ip route and most of it is still via 192.168.168.9 using eigrp.

I did

clear ip route *

clear ip route 192.168.168.0

The traffic is still going to the .9 router. I want all the traffic to go to the .88 one.

New Member

Re: changing the default gateway

I'm confused about something.

192.168.168.9 seems to be directly connected over the serial link (s0.30) and 192.168.168.88 is learned from .9

The address you're trying to get to is not in your routing table, therefore it would go to your default route (0.0.0.0).

Your default route points to .88, but to get to .88 you need to go through .9.

It would appear that you either need to go through .9 first, or that .88 comes through a different (frame?) connection but is not forming a neighbor relationship with your router.

Are the .9 and .88 routers different routers? Is there a seperate connection from the .88 router to this router? Does SH EIGRP NEIGHBOR give you anything useful?

Mick.

New Member

Re: changing the default gateway

.9 and .88 are different routers (both 1750s). Let me give a little more detail:

We have the .9 router and the .88 router. The .9 router routes all the traffic to our internet router. The .88 router is located in our ops center and we want all the internet traffic (and othe traffic) to go through the .88

Basically, the .88 needs to be our central router, not the .9 The .9 was in place before the .88 and due to really good (notice sarcasm) office politics some of the locations were brought up before the building was even constructed! We had to route the locations through the .9

Here is the kicker: the .9 location and the location of the internet router are also connected by a fiber link using some Catalysts. The .88 is also connected to the internet router location by a fiber link. There is no fiber link between the .9 and .88

This is all good and confusing, I know. I didn't set it up this way. We had wanted no fiber link between any of them (the costs of T-1 between them is real cheap compared to the fiber). Better yet, the fiber doesn't even go into our operations center (which kind of defeats the purpose of having it)

Anyway, enough ranting aside, I hope that gives some more info.

Also here is what the eigrp neighbors show as.

In the .9:

It gives me all the routers on the WAN

In the .88:

I get the .9

and I get the internet router

In the internet router:

I get .9

I get .88

In the router that I'm trying to push to the .88:

I get the .9

I hope this gives some more info.

New Member

Re: changing the default gateway

"In the router that I'm trying to push to the .88:

I get the .9"

Does this mean that you don't have an EIGRP neighbor relationship between .88 and the problem router?

You have a serial (s0.30 frame?) connection from the problem router to .9. Do you have a similar connection to .88? Once you see .88 as a neighbor and its advertising 0.0.0.0, you may find that you must tweak the BW setting on s.30 so that you'll favor .88 instead of .9.

Might have to work this out with diagrams over the phone! ;)

Mick.

New Member

Re: changing the default gateway

damn mickphelps you beat me to it!

I had the "Man ooh man this is going to be fun" line ready!!!

anyhow I'd like to add don't make .88 a nieghbour until the network is quite, the EIGRP 7000 needs time to "re-"converge and if you have a large network then it could take time

And BW means Bandwidth right?

New Member

Re: changing the default gateway

Well, I got it squared away. Thanks to openeing a TAC case.

I did make the .88 a neighbor. However, after pouring over the configs I had the serial connections shutdown!

Thanks for all your help guys! I was able to get more done than what I originally intended to do with your input. I've got some good backup ballancing running now.

I hope to return the favor someday...

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