Fun with NICs
We don't often think about Network Interface Cards or NICs until we've spent a lot of time figuring out that one has failed -- which they do from time to time. More often than not, problems with NICs can be traced to driver issues, and visiting the manufacturer's Web site for an update can solve those issues. But hardware failures do happen to NICs.
Given that you want your NICs to be both reliable and easily supported, it pays to buy NICs from major vendors in series in which very large quantities of this card family has been manufactured. Those two factors will influence how well supported a NIC is. I'm particularly partial to Netgear, but I also like Intel NICs; and I tend to stick with those two brands.
Given how cheap 10/100 Ethernet NICs have become, it's not a bad idea to have an extra NIC installed on your system. This is particularly true when the Ethernet connection you are using is an on-board chip on your system's motherboard, but it is true in general as well. An extra NIC that isn't being used doesn't impose a performance penalty, and offers you extra protection.
You may choose to create a dual-homed system (two NICs), and that will improve I/O in systems that are I/O limited. A second use of dual NICs is to create firewalls and proxy servers. But it is also a good idea just to have the extra redundancy in place for when things go wrong.
When using two or more NICs together, keep in mind that very often there are conflicts between multiple NICs, and these conflicts can be surprising. I've seen instances where two of the same vendor's NICs couldn't be successfully configured, but when you substituted another vendor's card in place of one of the two, both card functioned correct. So be aware of these types of problems.
Barrie Sosinsky (firstname.lastname@example.org)is president of consulting company Sosinsky and Associates (Medfield MA). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.