2 linux servers connected to a switch can't communicate with each other

Hi people:

I have 2 linux servers behind 1 switch. One of them controls my home
network routing (server1), while the other is being made into a dedicated
server (server2). The problem is this: The two servers can't communicate
with each other. They can't even ping each other. Therefore, I can't use
my laptop, which aquires internet from server1, to upload or access webpages
on server2.

Maybe the situation would be best described with a picture. So I am
attaching a diagram of how my networks are connected.

As you can see in the attached picture, 2 servers are connected to a switch.
Server1 governs another network, in which is my laptop. The problem is that
server1 cannot communicate with server2, not even pinging. Therefore, my
laptop, which is in the network under server1, cannot access server2 as
well.

I was told that with older verions of windows, they have the same problem if
NetBEUI protocol is not installed, unless the first 3 numbers of their IPs
are the same. And if NetBEUI is installed, the security is compromised.
So, I'm wondering what can I do with my 2 linux servers in order for them to
communicate with each other without compromising security.

Note that my isp allows 2 IPs. Therefore my 2 servers both have a unique
IP. Maybe that info is useful... maybe....

Honestly, I don't even know exactly what is the source of the problem right now. I don't even know what topic to search for on net. So, all helps are much appreciated. Thank you in advance.

Try a traceroute from server1 to server2, and vice versa. Post the results here.

Do server1 and server2 have the same netmask?

If server1 is doing your routing, it might be an idea to have server2 on the same network as the laptop and the family computer, and just use port forwarding to forward the services you want server2 to run to server2 using iptables.

Dear Alex:

I'm so glad to get a response from you. I haven't been able to find proper help anywhere.

Since I'm still a newbie, I asked my friend to do a traceroute for me. The result is:
1 - 30 hops all
* * *

According to him, the packets don't seem to be going anywhere. I can't really connect the server2 to the network under server1 because both servers are running web services. So what is another possible solution? And what subject should I read into for this kind of problem?

Also, if two computers are connected to a switch which in turn is connected to the modem, and the two computers assigned to different ips and different subnets by the isp's dhcp, how can those two computer talk to each other through the gateway in tcp/ip


Thanks greatly for your help.



Ray

That's not the full result. Here is an example of how it would look:


What you could do is put a firewall (and old redundant PC with three NIC's running Smoothwall will do fine) directly behind the DSL modem (connect the two together with a crossover network cable), set up a DMZ zone on one switch and put the web servers on that with port forwarding configured, then have the "green zone" on the other switch.

That would involve quite a bit of work, however (it is the setup I have at home). Please post the output of the following commands, run on both machines:

Maybe there is a simple mistake.