My current favorite ircd is ngircd. Super easy to install with just an apt-get install away. I usually hide everyones IPs on it cause nobody should just randomly know everybody elses IP. My only issue is making an IP count exception for connection bouncers. I had a server wide bouncer setup for a good number of my users.
As the maintainer of InspIRCd i'm biased towards it but ngircd is a pretty solid piece of software if you only want something which is simple and easy to set up without a bunch of fuss.
I have to look through the source code of other IRC server implementations regularly when checking for cross-server compatibility and looking through ngircd's source code is always a pleasure. Its extremely well written and easy to follow unlike the irc2-based IRC server implementations (UnrealIRCd, etc) which usually are a pain to find out what they're even doing.
Charybdis and ratbox are both installable in that fashion and easy to configure, not to mention they are also more stable, better-programmed, and better optimised for large networks than ngircd. With ngircd it's trivial to cause a netsplit by flooding; also, the dev Alex Barton admitted a while ago to neglecting proper input validation from server-to-server links, claiming servers are "trusted" ... I think after a while he finally agreed that it wasn't best practice and that all incoming data should be considered untrusted and hostile, but the fact that he didn't care at one point speaks volumes for the rest of his code which is probably still unsafe and unidiomatic to a degree. Meanwhile, ratbox and its charybdis successor both practise proactive defensive coding for untrusted input and I have witnessed no crashes with either, and I have been able to modify both their sources with relatively little trouble.
IP spoofing is possible on ratbox and charybdis; host cloaking is possible on charybdis but I would not depend on it. Personally I believe IP addresses are public information, but for those who don't agree with me, it's super easy to spoof hosts. Not to mention, both ratbox and charybdis support alternate I:lines (connection classes) for bouncers and the like.
Yep ngirc is awesome! Itβs so easy to set up a quick server without setting up Anope and all the services separately. The only problem is that I sometimes accidentally restart nginx instead of ngirc because of auto-complete :P
