Need help with connection problem...

Noods

Here is the problem I have.

I have two 2500 routers, a 1900 switch and 1 PC running a tftp. The routers are connected via a DCE/DTE cable. Router B is connected through a transceiver to the 1900 switch. The PC is also connected to the switch. I have OSPF enabled, and both routhers are picking up the routes of the other.

router A 10.2.1.2/16 --- 10.2.1.1/16 router B 10.1.1.1/16 --- 10.1.1.2/16 PC

I can connect to the TFTP server on my PC from Router B. I cannot connect to the tftp server on my PC from router A. I can ping up to 10.1.1.1 from router A, but not 10.1.1.2. What are some things that would cause this?

tunerX

Check the default gateway/router address on the PC and re-verify that all of the routes show up properly in both routers.

Noods

Can someone tell me what the highlighted text means?

distribution01>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 not set

10.0.0.0/16 is subnetted, 2 subnets
C 10.2.0.0 is directly connected, Serial0
O 10.1.0.0 [110/74] via 10.2.1.1, 00:03:34, Serial0

squawk1500

administrative distance / metric

Noods

Thanks! Still no clue on this one.

distribution01>traceroute 10.1.1.2

Type escape sequence to abort.
Tracing the route to 10.1.1.2

1 10.2.1.1 20 msec 16 msec 16 msec
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *

tunerX

It means that you can get replies to traceroute from the 10.2.1.1 interface but not from any thing farther. This could mean that your packets from routerA cannot get to the 10.1.0.0 network; or packets from routerA can get to the 10.1.0.0 network but the device on 10.1.0.0 cannot get any packets back to the 10.2.0.0 network.

If you can ping 10.1.1.2 from routerB, and you can ping 10.1.1.1 from routerA (you should be able to because the route is showing up in your routing table), then the problem is with distant end reachability from the pc to routerA.

I would imagine that the PC does not have the proper default route. On the pc you could try the following.

unix/linux
route add default 10.1.1.1 1

windows
route add 0.0.0.0 mask 0.0.0.0 10.1.1.1

Then try to ping the pc again. On unix/linux/windows you can use the following command to verify that you have reachability back to the networks that you want to get to.

netstat -nr

Noods

route add 0.0.0.0 mask 0.0.0.0 10.1.1.1

This worked! So, if I am looking at this correctly, the problem was that my computer didnt have a route to this router? Shouldnt the computer just send the packet to the default gateway in this case? Where can I learn more about that command? I can see myself encountering this problem again in the future, how can it be prevented?

Thanks for the help and incite!

tunerX

If that command worked then you do not have a proper default gateway. Or you have multiple default gateways and the wrong one is at the top of the list.

do the following

netstat -nr

If you have multiple 0.0.0.0 lines then you need to configure your adapters so there is only one default gateway address 10.1.1.1, otherwise you can use the route command to specify only the addresses in your lab will use the 10.1.1.1 address.

to find out more about route do a route /? at the command line