Blocking of Both Incoming and Outgoing?

I was trying to troubleshoot some SQL Server connections, when I ran
into some strange behavior that someone might be able to explain to
me.

I can remote connect to the server in question (Win 2003 Server), and
the network looks fine in general. Each machine has a single NIC:
Server1 192.168.0.10
Server2 192.168.0.11
Desktop 192.168.0.25

This is what I do:

I run SQL Server on all three machines (which is listening on port
1433). I can "telnet localhost 1433" on all machines without
problems.

1) I can "telnet 192.168.0.10 1433" without problems locally on
server1.
2) I can "telnet 192.168.0.11 1433" from my desktop
3) I cannot "telnet 192.168.0.10 1433" from my desktop

This sounds like inbound traffic is being blocked on server1. I
disabled the firewall alltogether so it's a little odd, but stranger
things have happened. Now to the weird thing:

1) I can "telnet 192.168.0.25 1433" without problems locally on
desktop.
4) I can "telnet 192.168.0.25 1433" from server2
3) I cannot "telnet 192.168.0.25 1433" from server1

Again, server1 is giving me trouble, now on outgoing traffic on port
1433. So it looks like both incoming and outgoing traffic on server1
is blocked. I've disabled the firewall alltogether, no luck. Any
ideas?

/Tomas