Here are some guidelines for hostnames which are allowed on IRC
First, what hostnames would be banned:
- descriptive hosts
- politically improper hosts
- 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
- Somewhat longer regular names which have obvious geographical addition
- Somewhat longer regular names which have 'type of connection' addition
Basically it's just a matter of common sense.