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New Member

Help needed with WAN routing issues.

We are having intermittent problems across our WAN, and have been unable to determine what is causing it.

- There are two networks involved; Net A - 10.1.3.0/24 and Net B - 10.1.2.0/24 and 200.200.29.0/24.

- There are two Cisco 1720 routers which route traffic over a T1 between the two networks.

- Net A's 1720 is NI=10.1.3.1 SI=192.168.255.2 (we'll call it Router A)

- Net B's 1720 is NI=10.1.2.6 SI=192.168.255.1 (we'll call it Router B)

- Net B has another router (200.200.29.5 and 10.1.2.5) which allows both subnets (10.1.2.0/24 and 200.200.29.0/24) on the same wire. (We'll call it router C)

- Router C is the default gateway for all devices on Net B.

- Router A is the default router for all devices on Net A

What is happening is when a device on Net A tries to ping a device on Net B's 10.1.2.0/24 network, it gets intermittent results. Sometimes it can ping a specific device, while sometimes it cannot ping that same device. I have noticed that once they are able to ping a 10.1.2.0 IP address, they seem to be able to do so for a while. However, if I log off of that machine and I come back later in the day, it wont be able to ping that same IP address. The wierd part is that they never have a problem pinging one of Net B's 200.200.29.0 addresses.

Here are the routing tables on each of the routers:

Router A

router eigrp 12

network 10.0.0.0

eigrp log-neighbor-changes

!

ip classless

ip route 0.0.0.0 0.0.0.0 192.168.255.1

ip route 10.1.2.0 255.255.255.0 192.168.255.1

ip route 200.200.29.0 255.255.255.0 192.168.255.1

Router B

router eigrp 12

network 10.0.0.0

no eigrp log-neighbor

!

ip classless

ip route 0.0.0.0 0.0.0.0 10.1.2.5

ip route 10.1.3.0 255.255.255.0 192.168.255.2

ip route 200.200.29.0 255.255.255.0 10.1.2.5

Router C (non-cisco)

ip route 10.1.3.0 255.255.255.0 10.1.2.6

Any input would be helpful. I have attached a connectivity drawing that will hopefully help.

1 REPLY
New Member

Re: Help needed with WAN routing issues.

The first thing that I would try is to turn off auto-summary (no auto-summary in the router eigrp 12 section on both routers). The default is summary, so both routers should have a directly connected route to 10.0.0.0/8. However, the static routes should be taking precedence over this route. Take a snapshot of the routing tables before and after you turn off auto-summary.

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