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Community Member

floating static routes

hello.all

I have a problem with floating static routes.

In my center,there is a 6509 and a 7513.In remote ,there is a 1720 with a wic-1t and a bri.all wic-1t and bri connect to 7513

The wic-1t is the primary interface with hdlc that there is running ospf.The bri is the backup interface of the hdlc that there is running floating static routes.

The problem is when the primary interface is down,the bri is brought up.i can ping the 1720 on 7513.but i can't ping 1720 on 6509.

I have redistribute static route into the ospf. and i can see the route to 1720 on 6509.(6509 and 7513 are running ospf)

on 6509.i trace to 1720.it forwar to 7513 and drop.why???????????

15 REPLIES

Re: floating static routes

From the info that you supplied, it appears that the ISDN connection is working properly. Did you verify this?

Assuming that it is, your problem may be caused by:

- Incomplete routing table on one of the machines involved.

- setting of - no ip classless-

Please post a sh ip route in a working and non-working situation and the config of your floating static for all three machines to investigate.

Regards,

Leo

Community Member

Re: floating static routes

The ISDN connection is working properly.Because i can ping 1720 on 7513

The routing table :

on 7513

working

O IA 10.10.10.0/26 [110/1563] via 10.20.20.134, 00:00:07, Serial8/0/1:20

non-working

S 10.10.10.0/26 [200/0] via 10.20.30.34

on 6509

working

O IA 10.10.10.0/26 [110/1564] via 10.100.100.1, 00:00:41, Vlan2

non-working

O E2 10.10.10.0/26 [121/20] via 10.100.100.1, 00:02:59, Vlan2

The problem is when the ISDN connection is working,i can ping 1720 on 7513

but i can't ping 1720 on 6509

but when i traceroute to 1720 on 6509.i found that the packet is forward to 7513 and then drop.why?

Re: floating static routes

What ip adress do you use for the ping from the 6509?

Try to use a different ip adress with an extended ping.

Please check any access-lists on the 7513 to see if one them blocks the path via ISDN for packets from the 6509.

Regards,

Leo

Silver

Re: floating static routes

The question is whether you can ping the 1720 from the 6509 when the link is on the primary. My guess is that the 1720 does not knows route to the ip address of the outgoing interface on the 6509.

Community Member

Re: floating static routes

When the link is on the primary,i can ping 1720 from 6509.It is working properly.

Community Member

Re: floating static routes

Try entering the static routes manually. I have run in to problems with the redistribute static route command working correctly

Bronze

Re: floating static routes

What do the floating static routes in the 1720 look like? It sounds like it is not finding the network of the 6509 through the backup link.

Community Member

Re: floating static routes

The floating static routes on the 1720 is ip route 0.0.0.0 0.0.0.0 bri0 200.

so i think the route on 1720 is no problem.

Community Member

Re: floating static routes

O E2 10.10.10.0/26 [121/20] via 10.100.100.1, 00:02:59, Vlan2

the route on 6509 is ok.when traceroute to 1720,6509 forward the packet to 7513 and then *.

so i think the redistribute static route is working correctly.

Community Member

Re: floating static routes

i resolve the problem

on 1720 the floating route is

ip route 0.0.0.0 0.0.0.0 bri0 200

but it don't work

when i change the route to

ip route 0.0.0.0 0.0.0.0 10.20.30.33 200

it is working porperly.

but why this,I don't know.

Silver

Re: floating static routes

Can not answer this question without seeing your config

Bronze

Re: floating static routes

A common error is to point to route to the physical interface (BRI) when a dialer interface is being used and should be used in the route statement.

Community Member

Re: floating static routes

it means on interface bri0 ,i must not point a route to physical interface .

why£¿

can you give me some detail for that?

Community Member

Re: floating static routes

On 1720 you should use ospf over demand circuit instead of floating static route.Config the command 'ip ospf demand-circuit' on the bri interface.When the primary link is down, 1720 will not recieve the ospf update from 7513 if you use static route.It dosen't know how to reach 6509 so ping packets from 6509 can't return.

Bronze

Re: floating static routes

Not true, dont use routing protocols if you dont need to. The question is why you need ospf on the primary circuit if a static default route works for the backup. Two static defaults with a higher metric on the backup would do the trick normally.

However, that said, I did set a link up like this when the remote router had trouble identifying failures in the frame relay network. We put ospf on the primary link and fed the remote a default route through ospf. If ospf lost the learned default route the static one through the backup link would be used.

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