Why cant I ping to different intereface when route is there

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Feb 5th, 2008
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All our devices are on vlan 1 in one building. However, we are trying to implemenet a new link. All devices

are using the 192.168.1.0 Network. However we are trying to add 192.168.21.0


On our 2950 switch we have 3 routers attached


Users have are given 2 default gateways via DHCP-One Gateway From Router A and the other from Router B


Router A-192.168.1.252

Router B-192.168.1.245


Router C will be the new subnet and Gateway -192.168.21.236


From Router B I can ping the 192.168.21.236 interface.




RouterB#sh ip route 192.168.21.236

Routing entry for 192.168.0.0/16, supernet

Known via "static", distance 1, metric 0


But from router A I cant

router A>sh ip route 192.168.21.236

% Network not in table


From my desktop on the 192.168.1.X subnet, I can ping the 192.168.21.236 interface. Perhaps I using Router B gateway when I do this??


However, when I switch over to the 192.168.21.X subnet, and use the .21.236 on router C-as my default gateway I CAN'T ping Router A but can Ping router B



BUT I have a route to the entire 192.168.1.0 network...via connection to router B. This would include a route to router A


Router A-192.168.1.252

Router B-192.168.1.245



Router C #sh ip route 192.168.1.252

Routing entry for 192.168.1.0/24

Known via "connected", distance 0, metric 0 (connected, via interface)

Redistributing via ospf 100


RouterC #ping 192.168.1.252

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.252, timeout is 2 seconds:

...

Success rate is 0 percent (0/3)

RouterC#ping 192.168.1.245


Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.245, timeout is 2 seconds:

!!!!!




However, only when I log into router B-can I ping router A


One thing I failed to mentioni is that Router C has a Primary and Secondary interface.


On Router A-the secondary is pingable but the primary is not-it is also showing connected even though there is a switch between them


RouterA#sh ip route 192.168.1.236

Routing entry for 192.168.1.0/24

Known via "connected", distance 0, metric 0 (connected, via interface

Redistributing via eigrp 1

Routing Descriptor Blocks:

* directly connected, via FastEthernet0/0




I'm stumped



I see no access lists applied to any interface on Router A that would deny ICMP


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gauravshar@hcl.in Tue, 02/05/2008 - 10:00
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Hi just post your show run output here for all three routers. If I'm getting your problem correctly you should look for 'ip classless' command on all routers. Implement it if it is not there in your running config.


Moreover, post 'show run' output as well.


--gaurav

Edison Ortiz Tue, 02/05/2008 - 11:24
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Router B has a static route to Router C as shown here:




RouterB#sh ip route 192.168.21.236

Routing entry for 192.168.0.0/16, supernet

Known via "static", distance 1, metric 0




Add the same static route on Router A.


HTH,


__


Edison.

nygenxny123 Tue, 02/05/2008 - 18:43
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Hi Edison,


Since I can ping the secondary interface on Router C from Router A. Shouldint I also

be able to ping the primary interface on Router C from Router A?


router c

secondary 192.168.1.236

primary 192.168.21.236

Edison Ortiz Tue, 02/05/2008 - 21:04
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The secondary IP is on the same subnet as the primary IP on Router A, no need for routing.


On Router A, do the following:


ip route 192.168.21.0 255.255.255.0 192.168.1.236


HTH,


__


Edison.

gauravshar@hcl.in Wed, 02/06/2008 - 00:29
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hi,


What output do you get for 'show ip route 192.168.21.0' @ Router A. What is the default route @ router A if you have one?


--gaurav

nygenxny123 Wed, 02/06/2008 - 06:08
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Here is the sh ip route to the primary ip interface

RouterA#sh ip route 192.168.21.0

% Network not in table


Here is the secondary IP

Router A#sh ip route 192.168.1.236

Routing entry for 192.168.1.0/24

Known via "connected", distance 0, metric 0 (connected, via

Redistributing via eigrp 1

Routing Descriptor Blocks:

* directly connected, via FastEthernet0/0

Route metric is 0, traffic share count is 1



the default route for router A actually goes to our ISP.



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