WAN routing - Not able to ping Directly

[dakshash_shah]

I have a question in regards to 2 routers connected over a Private T1 Link.

They are both new 2821 Routers. One is in LA and the other one is here in DC(our HQ office).

I link is up and I can telnet and ping the DC router(I sit in DC) and once I am in the DC router, I then can telnet and ping the LA router.

But why can't I telnet or ping the LA directly from here? Would it be a IP addressing issue or a routing issue?

We use EIGRP.

Here is the DC Config for the IP addressing and EIGRP Route:

Gateway of last resort is 172.16.1.254 to network 0.0.0

C 172.16.0.0/16 is directly connected, GigabitEthern

10.0.0.0/8 is variably subnetted, 2 subnets, 2 mas

C 10.10.10.250/32 is directly connected, Multilin

C 10.10.10.248/30 is directly connected, Multilin

S* 0.0.0.0/0 [1/0] via 172.16.1.254

controller T1 0/0/0

framing esf

linecode b8zs

channel-group 1 timeslots 1-24 speed 64

!

controller T1 0/0/1

framing esf

linecode b8zs

channel-group 1 timeslots 1-24 speed 64

!

!

interface Multilink1

ip address 10.10.10.249 255.255.255.252

no ip route-cache cef

no ip route-cache

no ip mroute-cache

no cdp enable

ppp multilink

ppp multilink fragment disable

ppp multilink group 1

!

interface GigabitEthernet0/0

ip address 172.16.0.100 255.255.0.0

duplex auto

speed auto

!

router eigrp 1

redistribute static metric 1000 100 255 1 1500

network 10.0.0.0

network 192.168.99.0

no auto-summary

!

ip classless

ip route 0.0.0.0 0.0.0.0 172.16.1.254

no ip http server

Here is the config for the LA side:

Gateway of last resort is 10.10.10.249 to network 0.0.0.0

S 172.16.0.0/16 [1/0] via 10.10.10.249

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

C 10.10.10.248/30 is directly connected, Multilink1

C 10.10.10.249/32 is directly connected, Multilink1

D*EX 0.0.0.0/0 [170/5145600] via 10.10.10.249, 4d00h, Multilink1

controller T1 0/0/0

framing esf

linecode b8zs

channel-group 1 timeslots 1-24 speed 64

!

controller T1 0/0/1

framing esf

linecode b8zs

channel-group 1 timeslots 1-24 speed 64

!

!

interface Multilink1

ip address 10.10.10.250 255.255.255.252

no ip route-cache cef

no ip route-cache

no ip mroute-cache

no cdp enable

ppp multilink

ppp multilink fragment disable

ppp multilink group 1

!

interface GigabitEthernet0/0

ip address 10.15.0.1 255.255.0.0

duplex auto

speed auto

!

router eigrp 1

redistribute static metric 1000 100 255 1 1500

network 10.0.0.0

network 64.0.0.0

no auto-summary

!

ip classless

ip route 0.0.0.0 0.0.0.0 10.10.1.254

ip route 172.16.0.0 255.255.0.0 10.10.10.249

no ip http server

Can someone look at this and let me know if anything is wrong?

Shouldn't I be able to telnet directly to the LA side? Also, please note that I am doing MultiLinking of two T1's.. the 2nd T1's are not up yet, would that be a problem?

Thank you for your help on this.

[Georg Pauwen · Accepted solution]

Hello,

where are your default routes pointing to ? Since you say that the routers are connected by a T1, does that mean they are directly connected ? Or are the next hops defined in the default routes the IP addresses of firewalls ?

Which IP address are you trying to ping from ? If it is in the 172.16.0.0 range (as is the IP address of your GigabitEthernet interface in DC), try to advertise that network in EIGRP and see if that makes a difference:

DC Router

router eigrp 1

network 172.16.0.0

Regards,

GP

[Richard Burts]

I have looked at the information that you posted and have these comments about it:

- it appears that the multilink is correctly configured.

- it should not make any difference if the second T1 is not up yet.

- it appears that EIGRP is configured to include the multilink from HQ and is working.

- the EIGRP config at HQ includes this network statement:

network 192.168.99.0

which does not match any interface on the router. Where did this come from? Though it should not create a problem I would suggest cleaning this up.

- The Gig Ethernet interface at HQ is not included in EIGRP.

- the HQ router has a static default route with the next hop being somewhere on the Gig Ethernet. The static default route is redistributed in EIGRP.

- The LA router appears to have the multilink correctly configured.

- EIGRP at the LA router does include the multilink in EIGRP.

- there is some evidence that EIGRP is working because the static default route from HQ does appear as a redistributed route at LA.

- The Gig Ethernet at LA (10.15.0.0) should be in the routing table at HQ but it is not. Either this indicates that there is a problem in EIGRP or it indicates that the interface in LA is in a down state.

It would help to know what address does work for ping and telnet and what addresses do not. But based on what you describe I will make a guess at the problem. I believe that the thing that would be most likely, given your description of the problem, is that the default gateway on your PC is not configured correctly.

Please check your PC and verify whether its default gateway is set to 172.16.0.100.

HTH

Rick

[francisco-vazquez]

You just need to avertise LA Network in EIGRP

router eigrp 1

network 10.15.0.0

HTH

[francisco-vazquez]

Sorry, the network is 172,16.0.0 in DC router.

[Richard Burts]

Since we do not know much about the environment at HQ we can not know yet whether the 172.16.0.0 needs to be advertised in EIGRP.

Advertisement in EIGRP is for the Enterprise network. And we do not know whether the 172.16.0.0 is part of the Enterprise network or whether it is an outside network (perhaps in a colocation facility or perhaps a building LAN provided by the building management and/or ISP. The fact that there is a ststic default route with next hop on the LAN suggests to me that they intentionally did not include the HQ LAN into EIGRP.

Perhaps Dakshah who posed the original question can clarify this?

HTH

Rick

[cisco_network]

Hi,

Dakshah ,I have gone through your config .I would like to give some suggest if you can use.

1.Pls advertise your gigabit ethernet interface network and multilink network with no autosummary at both router.

2.Remove static route from LA router.

i hope Then u will be able to ping after that.

Regards

Abhi

[Richard Burts]

I have thought about this situation some more and have a few more comments.

I believe that it is important to know what is the default gateway on the PC that Dakshah is using at HQ. Given that the default route on the HQ router is 172.16.1.254 I am guessing that the PC default gateway is also 172.16.1.254.

If my gess about the default gateway is correct then I believe it leads to another important question. The LA router and the HQ router know how to get to outside addresses by going through 172.16.1.254, but does the router at 172.16.1.254 have routes that know how to get back to HQ and LA.

If the PC default gateway is 172.16.1.254 and if that router does not have routes back to the subnets of 10.0.0.0 that are on LA and HQ then it would explain the situation that Dakshah describes.

There is another question that Dakshah can clarify for us: what is the nature of the network on Gig Ethernet at HQ (the 172.16.0.0 network). The current config does not run any dynamic routing protocol over it and I am guessing that the router at 172.16.1.254 does not run any routing protocol on it. So should there be a routing protocol running over this network (as several people have suggested), or should all the routers on that network just use static routes to identify each others networks? What is the intended usage of this network?

HTH

Rick

[dakshash_shah]

thank you all for your reply.

I advertised the 172.16.0.0 router in EIGRP and now I can telnet and ping from my workstation to the LA side.

My workstation has a 172.16.X.X address.