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Community Member

Can only ping using Extended Ping feature

I am trying to set up some of our ADSL Routers with GRE Tunnels but some will not work. On the routers that do not work, the normal ping will does not work to start with. I can ping using the extended ping feature, but a straight forward ping does not.

Other routers where the ping works, the GRE Tunnel works straight away.

Anybody got any ideas?

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Can only ping using Extended Ping feature

Hi Gary,

Beside believing that its a routing issue from the destination, it might be a routing issue within your provider kindly consolidate with them.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

17 REPLIES

Re: Can only ping using Extended Ping feature

Hi,

If the normal ping doesn't work while the extended ping works --> When doing normal ping the ping packet source uses the IP address of the outgoing interface, accordingly your symptoms means that the ip of the outgoing interface is not routable from the destination side, while the IP address you use in extended ping has available routing from the destination side.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

Hall of Fame Super Gold

Re: Can only ping using Extended Ping feature

Gary

I suspect that Mohammed is probably correct in his identification of the problem. But I believe it would help confirm this if you would tell us what you specify when you do the extended ping. Most especially in the extended ping do you specify a source address? What else do you specify when you do the extended ping?

HTH

Rick

Community Member

Re: Can only ping using Extended Ping feature

Hi Rick

I specify the Target IP address (the hub site, if you will) and then specify the Ethernet0 interface as the source address. Those are the only two items that I specify.

What I can't understand that 6 other routers (with exactly the same config apart from different LAN/WAN IP addresses, and the same IOS version) can ping without using the extended feature.

Regards

Gary

Re: Can only ping using Extended Ping feature

Hi Gary,

I do believe its a routing issue from the destination, it can only see your Ethernet IPs but not your WAN IPs.

HTH,

Mohammed Mahmoud.

Hall of Fame Super Gold

Re: Can only ping using Extended Ping feature

Gary

Thank you for the additional information. I believe that we are moving toward an understanding of the issue. That fact that you specify the source address as the Ethernet does help to confirm the suggestions that it is a routing issue to the interface that would be the default source address. One way to investigate this would be to note the outbound interface address of the router where you have this problem and then go to the hub router and do show ip route . My guess is either that the router will say something like address not in the routing table or it will point out some other interface as the way to get to the address.

It might also help us discuss this issue if you can provide a bit of information about the topology of the network.

HTH

Rick

Community Member

Re: Can only ping using Extended Ping feature

Hi Rick

As far as topology goes, we have a central hub router (7204) connecting over 30 remote sites. The remote sites mainly use IP Clear over ADSL using BGP. Of the 17 sites configured in this way, only 4 sites do not ping in the normal way despite being configured in exaxctly the same way (the configs are copied from a template with only IP Addresses being changed). The hub 7204 can ping all the remotes sites (incl the "4") with no problem at all.

Hope this helps

Gary

Re: Can only ping using Extended Ping feature

Dear garybeach,

How about the PING result from the hub side toward the 4 remote site Serial/WAN interfaces IP address? What is the source/destination of your GRE tunnels (Ethernet/Serial)?? it's seems that the GRE tunnels configured to use your Ethernet Address as a source and destination and there is no routing at all for such 4 remote sites wan interfaces.

Best Regards,

Mounir Mohamed

Community Member

Re: Can only ping using Extended Ping feature

Hi Mounir

I haven't been able to set up the Tunnels yet because the direct pings do not work and as such the Tunnel does not stay up because the keepalives are not getting through.

The Hub side pings the remote sites - no problem

Regards

Gary

Re: Can only ping using Extended Ping feature

Hi Gary,

Beside believing that its a routing issue from the destination, it might be a routing issue within your provider kindly consolidate with them.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

Hall of Fame Super Gold

Re: Can only ping using Extended Ping feature

Gary

Did you try what I suggested and on the hub router do show ip route for the outbound interface of one of the routers that does not work correctly?

Perhaps a bit more detail might help. When you ping from the remote are you pinging to the outside interface of the hub or to its inside/LAN address or a loopback?

Also it might help us to know whether the hub router is using some routing protocol or is using static routes to get to the remote routers.

HTH

Rick

Community Member

Re: Can only ping using Extended Ping feature

Hi Rick

Yes I did. As the hub router is using BGP it showed exactly the same routing information for both a remote site that works and one that does not (showing the same next hop router IP address as the BGP neighbor).

When I ping from the remote site, I have tried pinging the Inside LAN and loopback addresses.

The hub router is using BGP and redistributing BGP into EIGRP.

Hope this helps

Regards

Gary

Re: Can only ping using Extended Ping feature

Hi Gary,

Can you please confirm your topology, to trace the problem.

BR,

Mohammed Mahmoud.

Hall of Fame Super Gold

Re: Can only ping using Extended Ping feature

Gary

Thanks for the additional information. To clarify: on the hub router if you do show ip route for the Ethernet of the remote router and for the outside interface of the remote router you get the same results for both of them? They both show the provider BGP router as the next hop? If so I wonder if it points to some routing issue within the provider network. Can you check with them about this possibiliity?

Think it might also be interesting if you would post the output of traceroute from the hub router to the remote router outbound interface and traceroute to the remote router Ethernet. Do they both take the same path through the provider network?

HTH

Rick

Community Member

Re: Can only ping using Extended Ping feature

Hi Rick

I must admit I'm beginning to think the same. I will contact BT and see what they have to say about it.

Here is the output as requested for .38 (not working) and .52 (working)

7204VXR#sh ip route 192.168.38.0

Routing entry for 192.168.38.0/24

Known via "bgp 64**1", distance 20, metric 0

Tag 2856, type external

Redistributing via eigrp 1

Advertised by eigrp 1 metric 2000 200 255 1 1500

Last update from 217.32.***.105 7w0d ago

Routing Descriptor Blocks:

* 217.32.***.105, from 217.32.***.105, 7w0d ago

Route metric is 0, traffic share count is 1

AS Hops 1

7204VXR#sh ip route 192.168.52.0

Routing entry for 192.168.52.0/24

Known via "bgp 64**1", distance 20, metric 0

Tag 2856, type external

Redistributing via eigrp 1

Advertised by eigrp 1 metric 2000 200 255 1 1500

Last update from 217.32.***.105 6d22h ago

Routing Descriptor Blocks:

* 217.32.***.105, from 217.32.***.105, 6d22h ago

Route metric is 0, traffic share count is 1

AS Hops 1

I was just doing the traceroute to the loopback address and it just goes in a loop within the BT network...we may have found the problem. I am getting on to then straight away!

Will keep you posted.

Gary

Community Member

Re: Can only ping using Extended Ping feature

Thanks for all your help guys.

Turns out the Telco ahd mis-configured these sites with different loopback addresses to the ones that we had given to them.

As soon as they had changed their configs, the 4 sites worked perfectly.

Many Thanks again

Gary

Hall of Fame Super Gold

Re: Can only ping using Extended Ping feature

Gary

Thanks for letting us know that the problem is resolved and how it was resolved. And thanks for using the rating system to indicate that the problem is resolved. It makes the forum more useful when people can read about a problem and know that they will read the solution to the problem.

I encourage you to continue your participation in the forum.

HTH

Rick

Re: Can only ping using Extended Ping feature

Hi Gary,

I am very glade that we had succeeded helping you out of this, thanks for rating all who helped you, and please always try coming back when facing any problems.

BR,

Mohammed Mahmoud.

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