[c-nsp] Low activity systems lose net connectivity

[Tauren Mills]

Hello,

I have a very simple network with about 5 linux servers, a cisco
3500XL switch and a 2600 router.

There is a problem with servers that have very little or no traffic.
The network interfaces on the low traffic servers seems to become
non-response after a very short period of time (as low at 15 seconds
of inactivity), and then existing connections timeout (such as SSH
sessions).

Servers that have consistent traffic to them don't have the problem.
Only servers that get sporadic or no traffic. And servers that get
traffic during the day, but not at night have problems at night, but
not during the day.

If I ping the low traffic server from another system, then it works
fine.  It only has problems when there is no network activity for it.
If a connection is stalled in this way, then starting a ping to the
server will often kick the connection going again.

My colo support team suggests that it may be a problem in how my
servers are being ARPed in my router.  Here is the router config:

Building configuration...

Current configuration:
!
version 12.0
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname router
!
enable secret 5 $1$XXXXXXXXXXXXXXXXXXXXXXXXX
enable password 7 XXXXXXXXXXXX
!
ip subnet-zero
!
!
!
!
interface FastEthernet0/0
 ip address XXX.XXX.XXX.XXX 255.255.255.248
 no ip directed-broadcast
 full-duplex
!
interface FastEthernet0/1
 ip address XXX.XXX.XXX.1 255.255.255.0 secondary
 ip address XXX.XXX.XXX.1 255.255.255.0
 ip access-group 104 out
 no ip directed-broadcast
 no ip proxy-arp
 arp timeout 120
!
ip classless
ip route 0.0.0.0 0.0.0.0 XXX.XXX.XXX.XXX
no ip http server
!
access-list 104 deny   ip 213.136.105.0 0.0.0.255 any
access-list 104 deny   ip any 213.136.105.0 0.0.0.255
access-list 104 deny   ip 194.102.224.0 0.0.0.255 any
access-list 104 deny   ip any 194.102.224.0 0.0.0.255
access-list 104 deny   ip 200.64.56.0 0.0.0.255 any
access-list 104 deny   ip any 200.64.56.0 0.0.0.255
access-list 104 deny   ip 213.131.131.0 0.0.0.255 any
access-list 104 deny   ip any 213.131.131.0 0.0.0.255
access-list 104 deny   ip 80.97.37.0 0.0.0.255 any
access-list 104 deny   ip any 80.97.37.0 0.0.0.255
access-list 104 deny   ip 209.67.60.0 0.0.0.255 any
access-list 104 deny   ip any 209.67.60.0 0.0.0.255
access-list 104 deny   ip 193.109.122.0 0.0.0.255 any
access-list 104 deny   ip any 193.109.122.0 0.0.0.255
access-list 104 deny   ip 195.47.220.0 0.0.0.255 any
access-list 104 deny   ip any 195.47.220.0 0.0.0.255
access-list 104 deny   ip 64.235.225.0 0.0.0.255 any
access-list 104 deny   ip any 64.235.225.0 0.0.0.255
access-list 104 permit ip any any
!
line con 0
 transport input none
line aux 0
line vty 0 4
 password 7 XXXXXXXXXXXX
 login
!
no scheduler allocate
end

Any thoughts on how to deal with the problem?

Thanks,
Tauren