I recently encountered a problem on a server that I manage where by the oidentd server didn’t seem to be working.
Manual tests worked, but connecting to IRC Servers didn’t.
I tried switching oidentd with ident2 and the same problem.
After switching back, and a bit of debugging later it appeared that the problem was that the IRC Servers were expecting spaces in the ident reply, whereas oidentd wasn’t giving them.
I then quickly threw together an xinet.d-powered ident server with support for spoofing.