I think the idea of an IT dictionary was mentioned in the thread where users could wish for a new, Pleco-curated dictionary. So if there already was one, Mike or someone else would probably have said so.
I agree it would be nice to have a comprehensive resource, though I guess the combination of English-speaking Chinese learner and IT specialist, which would be the target audience for such a dictionary, isn't all that common. People who are proficient in these two areas could almost be expected to be able to figure it out on their own using Google/Baidu and the other available dictionaries.
Just for fun, I checked Pleco's other dictionaries, IP address is, as one would expect, none other than "IP地址", the word firewall is the same as for a real firewall, namely "防火墙", or long "电脑网络防火墙", server is "服务器", and netmask is "掩码" or "IP地址掩码“. So you can already piece together something. Perhaps you know the trick whereby you look up a term in Wikipedia, then switch to the Chinese language Wikipedia. Then you can google it if needed and see if Baidu Baike's definition agrees with the meaning you're looking for. For netmask, I first found "subnetwork" in Wikipedia, switched to Chinese, looked for the netmask term and verified it with Baidu Baike.
François is quite right, of course, one should be able to get by with the English terms in most everyday situations. But I agree that it's nice to be able to understand it with certainty when someone uses the Chinese variant.
I do have a set of 75 flashcards with mostly basic IT terms, pretty general ones, but perhaps still useful. FWIW, I include it here.