Routing problem

[Sajtz]

Hi!

I have a problem. Im trying to do a "route add 10.1.3.4 193.0.2.4" but it just answers with "<b>network unreachable[/b]".

The computer I want to reach (10.1.3.4) is on an external network and is connect to the internal network with the gateway 193.0.2.4.

Here is the tricky part. The external computer can ping the Internal ( the one I´m trying to do an route add on ), but the Internal can´t ping the external ).

It´s not an issue of firewalls.

To help you further. The Internal computer can ping the gateway, and the gateway can ping the external but, as said, the Internal computer can´t ping the external ( but the external can ping the internal).

Any help appreciated.

 

[ChrisAC]

The external computer can ping the Internal"

If this is the case then the internal computer already has a route, otherwise it wouldn't be able to send back the icmp replies.

If the external computer is getting a successful ping then this means that traffic has gone to the internal PC and then the internal PC has sent a reply back, so routing works both ways!

Chris.

**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[123tech]

Also make sure the external computer will allow icmp request. I'm not sure what the external computer is, but if it's XP, 2000 server, or 2003 server it might not respond to icmp request.

 

[Sajtz]

Hi again. Thnxs for the replys.

I will give you some more details:

This is the machine I want to set up on the internal net:

lo0: flags=1000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4> mtu 8232 index 1
inet 127.0.0.1 netmask ff000000
hme0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
inet 200.0.4.16 netmask ffffffc0 broadcast 200.0.4.63
ether 8:0:20:fa:3d:34
hme1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 3
inet 200.0.4.76 netmask ffffffc0 broadcast 200.0.4.127
ether 8:0:20:fa:3d:34

When I do an route add like this:

route add 193.0.4.169 193.0.4.154
add host 193.0.4.169: gateway 193.0.4.154: Network is unreachable

Alright I think then, the computes are on different net and I have to route to the gateway 193.0.4.154 in some way.

But when I route from an another computer on the internal net It works correctly. I can, after the route add, ping the machine 193.0.4.169, so it shouldn´t be any wrong with the external machine.

Since there are 2 NICs on the internal machine I did the following:

hme1:
traceroute -s 200.0.4.76 193.0.4.169

traceroute to 193.0.4.169 (193.0.4.169) from 200.0.4.76, 30 hops max, 40 byte packets
1 200.0.4.1 (200.0.4.1) 0.885 ms 0.493 ms 0.491 ms
2 193.0.4.169 (193.0.4.169) 0.543 ms 0.438 ms 0.445 ms

hme0:
traceroute -s 200.0.4.16 193.0.4.169

traceroute -s 200.0.4.16 193.0.4.169
traceroute to 193.0.4.169 (193.0.4.169) from 200.0.4.16, 30 hops max, 40 byte packets
1 200.0.4.1 (200.0.4.1) 0.827 ms 0.466 ms 0.489 ms
2 *^C#

So when I use the hme1 NIC i can make a traceroute, but I still can´t make an route add using that NIC.

Any ideas?

br
Petter

 

[chieftan999]

Are you trying to add a route to the NIC directly rather than the network address?

If so you cannot do that.

For example:

A PC with the address 192.168.172.12 / 24
The network portion of the above address is 192.168.172 and the host is 12.

The route add command would be to the network address and NOT the host address so would look like:-

route add 192.168.172.0 255.255.255.0 (next hop)

Remember that you have to put in a return route as well.