Weird No route to host

[Glen Reesor <Glen.Reesor@telus.net>]

I'm having a strange problem on my LAN....

I have two computers: jg-tower and jg-laptop.  Upon initial boot, here's what I see:

ssh jg-laptop to jg-tower     Fails with "No route to host"
ssh jg-tower to jg-laptop     Succeeds

Now, I can ssh jg-laptop to jg-tower

Here's the first interesting part: the connection from jg-tower to jg-laptop can be via any protocol, even if blocked by jg-laptop's firewall.  For instance, trying to connect to jg-laptop:631 (which is blocked by Guarddog on jg-laptop) will allow subsequent ssh from jg-laptop to jg-tower to succeed.

Here's the second interesting part: do nothing on both computers for ~10 minutes and ssh from jg-laptop to jg-tower will fail again (No route to host), until I try connecting from jg-tower to jg-laptop again.

On the surface, it appears that jg-laptop has no knowledge of jg-tower unless it sees packets from it, and then forgets that routing info if not used for ~ 10 minutes.

The configuration on both machines is identical:

• Both running wireless, configured via network-manager-kde
• Output from "route" shows the same thing on both computers
• Both computers are connected to my wireless router
• Both computers can connect to internet hosts via http
• Both computers are running Guarddog, which allows ssh from hosts on my local network
  

Any help would be greatly appreciated!