I have obtain two PowerEdge 2800 servers FREE. Nice right! They have a hardware setup that interests me and I am curious of why they may have them setup they way that they are. The servers are labeled Server 1 and Server 2 and they are identical in setup. Of course the hard drives were pulled but they were originally shipped with Windows 2003 Std. PowerEdge servers have 2 built on on 1gb NIC's. But they added two more Dual NIC cards on each server. Making them each have 6 NIC's. These servers came from an Alarm company. I am just curious to why they had them setup this way. Maybe they didn't have a switch? I didn't get to pull these servers myself. My brother does construction and they were left behind by the company when they were demoing the building and of course he knew I may want these and of course I did. I will make them Linux boxes. Does anyone have any idea's of what kind of setup they "might" have been used for? The reason I want to know is it might be something I have not used before and could be useful but I can not think of anything to why they would have so many ports. I assume one server was a backup domain controller I guess. But it seems like over kill of network ports.

The only reason I can think of right off is to avoid the use of a switch. Thus avoiding any perceived latency issues, or configuration snaffoos? They might have thought avoiding a switch would tighten the security of their network with everything forced to static IP's and no way for an external intruder to tap into the network through an appliance? Think of direct connecting one of the NIC's to say, a SQL server and it's backup server. And another to a domain controller, etc. So one server to another server. Or maybe they had that many inbound lines from their ISP and they put each on it's own WAN connection?

This is all guess work

That many NICs would typically indicate the use of trunking/teaming.

The high number of NICs suggests more than one network segment, teaming nonwithstanding. They may have had a dedicated storage network for iSCSI or AoE. It could also be that the servers were running some sort of High Availability service, with some of the NICs being used for heartbeat signaling between the nodes.

2+2*2 NICs looks like they used to team or bond 2 NICs together for redundancy and connect the server to 3 different networks.
Why they had dedicated networks is hard to say without more background information, but it could possibly be a management network, a production network and a intranet. There are many companies out there building didicated networks for special uses to make sure one can't interfere with the other. Maybe they weren't even using TCP/IP on some of the networks but other protocols.

I'd go for teaming the interfaces, which is more likely the more common practice nowadays than connecting to dual WAN interfaces. Teaming+load balancing i guess??