Google gave me conflicting answers for this one. Some believed that most networks take the lazy attitude to DNS lookups and simply set your hostname to whatever RDNS throws up while others said it was validated bi-directionally.
What, in your experience, is the "standard" procedure?
Yes, it's validated both ways, although there are some older IRCD versions which did not do this. The lazy attitude didn't work very well for IRC servers because people could easily provide a rDNS pointing to a hostname they didn't control. Since vanity hosts are popular, if this wasn't done, we'd see everybody connecting with hosts like "lulz.i.own.microsoft.com".
Further, some IRCDs will reveal the actual IP in whois as well as the resolved as a counter to short TTL times and forward DNS entries being removed shortly after connection.
