Router can ping, but a host can't

[RobBryson]

Hello all,

Cisco-GP#show ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.32.201 to network 0.0.0.0

C 192.168.4.0/24 is directly connected, FastEthernet0

D 192.168.32.0/24 [90/2172416] via 192.168.32.201, 21:50:54, Serial0

C 192.168.3.0/24 is directly connected, Ethernet0

S* 0.0.0.0/0 [1/0] via 192.168.32.201

In the above fa0 is 192.168.4.1, eth0 is 192.168.3.12 and is attached to a 5GHz radio 192.168.3.11. Se0 is un-numbered and is a T-1. Currently the radio link is down but normally the EIGRP route would include the eth0 interface. Here's the problem... from the fa0 interface (telnet) or the console I'm able to ping the radio and telnet to it, but from a pc (192.168.4.19, default gateway of 192.168.4.1) all attempts to ping 3.11 (or 3.12) time out. Clearly the router knows the 3.0 subnet exists on eth0, why can't I ping it from a host in the 4.0 subnet? Any help will be appreciated.

Rob

[john.tharp]

Rob,

I'm sure you checked this already, but does radio device have a default gateway defined? Can you get into the radio device and ping the workstation?

[ruwhite]

The radio may not know the path back to 192.168.4.0/24, which is where the host is pinging from. To test this, use an extended ping on the router. From the command prompt, type ping, then return (nothing after the ping command). You'll get a series of options--put in the destination address where it asks, etc. When you get to "extended options," type "y" for yes.

Now, you'll get some further questions, including "source interface or ip address." Here, type in the ip address of 192.168.4.1.

If the ping works, the problem is probably on the host side (not likely, since it sounds like you've already checked your default gateway there). If it doesn't, then the radio doesn't know how to get to 192.168.4.0/24.

:-)

Russ.W

[RobBryson]

Looks like it is indeed the default gateway. The radio currently has a default gateway of 192.168.3.1 which is at the other end of the radio link... great when the link is up, but useless when it fails. I'll have to go on-site to reprogram the radio, but I'm pretty sure this will fix the issue. Thanks!