Question : Problem: Server communication within DMZ

We are having sporadic communication issues in our DMZ, which consists of one Cisco Catalyst 3550 10/100 switch and about 15 Windows servers connected to a Cisco Pix 515e firewall.  We have no problems reaching the servers from the inside or outside networks or even from the Pix itself.  Our problem is, the servers lose connectivity to each other through the one switch.  This is the third switch we have tried, so are pretty determined it is not an issue with the switch.  All ports on both the switch and servers are hard coded to 100/full.  We have no filters or restrictions of any kind configured on the 3550 switch, however in our testing we cannot ping one or two particular servers from another server, then suddenly the ping will respond.  Have verified no duplicate IP addresses and double checked the server mac addresses with what we see populate the switches arp table.  Any other suggestions would be helpful as we are stumped.

Answer : Problem: Server communication within DMZ

Problem resolved!

After sending a full capture of switch traffic to Cisco during a communication outage, they recommended we apply this command to our Pix DMZ interface which appears to have solved our intermittent problems.

sysopt noproxyarp dmz

Thank you for your assistance in trying to narrow down the issue!