Here are some guidelines for hostnames which are allowed on IRC

First, what hostnames would be banned:

- descriptive hosts
eg. is.an.evil.coder.of.cluesoft.be

- politically improper hosts
eg. is.playing.microsoft.flight.simulator.with.bin.laden.be

- long hosts (subwise, meaning many dots)
eg. goddamned.why.isn.t.it.legal.to.drive.and.drink.alkohl.be (11 dots)

When you make a hostname please keep RFC1178 in mind.

What hostnames would be allowed:

- Regular computername.domain.tld
eg. xs3.xs4all.nl

- Somewhat longer regular names which have obvious geographical addition
eg. cp104937-a.dbsch1.nb.nl.home.com

- Somewhat longer regular names which have 'type of connection' addition
eg. s340-isdn108.dial.xs4all.nl

Basically it's just a matter of common sense.