Re: problems renewing logins [ timeout issues? ]

I previously posted a query about an intermittent problem that has only 
started to occur recently; in which I said:

> ... *sometimes* our client computer seems to get "cut off"

I think that this has something to do with the "IdleTimeout" (ARP table) 
feature, judging by the logged message "Expiring inactive connection from ..."

I have seen client connections getting "expired" by Gateway.pm only 2 or 3 
minutes after successfully renewing their login.

So now I do not think they are failing to renew correctly, I think that 
despite renewing regularly (every 7.5 minutes) they are losing their ARP table 
entries and that this is tripping the IdleTimeout code.

Perhaps my settings are stupid; after all I finf the timeout settings a bit 
confusing so I could have made a mistake. We currently have :-

 LoginTimeout is set to the recommended 600 seconds (10 minutes)
 IdleTimeout  is not set, I believe the default is 300 seconds (5 minutes)

Any thoughts please?
Steve Platt