Hi,

The town hall in our small town currently has a Linux server I installed last summer. It's running CentOS 5. It currently acts as a mere file server, but I want to turn it into a gateway/firewall/proxy machine (and replace CentOS 5 by Slackware 13.37 in the process )

I wonder if I can simply add a classic PCI Ethernet card, the same type as the one found in your average desktop PC. Or does a NIC in this type of server differ from the one in a desktop PC, e. g. supposed to be more robust?

Currently there are about ten client desktops (half Windows, half Linux) and two big printers connected, so it's not a very busy server.

You're gonna connect the new interface to your internet router, right? In this case, supposing your internet bandwidth is below 1Gb/s (the nominal rate of a cheap NIC), I think you won't notice much difference between the entry-level and an expensive one.
Yes, there are ethernet card with hardware checksum of packets and some other nice features that can help reduce latencies but, assumed one card like that is not already there, will maybe best fit on the other side, the one with the clients attached (much more bandwidth involved).
Instead, squid will benefit of fast access disks to record and serve cached pages, so getting a small SSD to act as /var/cache/squid will surely rocket its performances

Thanks, ponce. In fact our Internet bandwidth is 1Mb/s, since this is the South French countryside. I'll keep in mind to install the new (cheap) NIC facing the Internet, and the onboard card facing the LAN. Though for storage I'll go with my usual RAID 5 disk array.

Ciao!

If you got plenty, you can also use ram (I usually configure squid with 1 or 2 Gb of cache), just remember to reinitialize squid's cache (squid -z) at every reboot.
Sorry if I look too performance freak, but I like to push thingies (for fun and profit).

Consider an Intel Pro 1000 MT for the LAN side, and use the onboard NIC for the WAN side. If the box is a normal x86 box your options are likely to be PCI and PCI Express; go for the latter if the budget allows. A server class adapter is preferable, even in a small business, especially if this box is going to be a gateway/file server/Squid proxy. My advice would be to use a second OpenBSD box purely for the firewall, and Slackware for Squid/Samba/NFS/whatever.

If you are using Software RAID use RAID 0 instead of RAID 5 or RAID 1 for your Squid cache. There is no need for redundancy with your Squid cache. Use RAID 1 + backups for the system, and RAID 5 + backups for your data.

I'd like to follow this advice as well as the one given below yours, but I'm working on a tight budget. This single machine acts as a file server as well as gateway/firewall/proxy, so it has to be RAID 5.