On 2011-04-04 01:53:15 +0200, Reindl Harald wrote: > > But the purpose of having a host in DNS is to be able to resolve it. > > I mean: you can't have a real hostname in the DNS if it is on a private > > network (unreachable because of NAT), can you? Well... I'm not sure. > > See below > > why not?
Because strictly speaking, due to NAT, the DNS would lie. I mean that the address would not be the address of the machine sending the mail, but the address of the router. > * you have a public ip > * make a a-record in some domain to this ip > * your isp have a ptr for this ip > * myhostname = your a-record > > EHLO/HELO, A, PTR are matching > where is the problem? They won't even necessarily match for some machines. For instance, one of them is a laptop, which is not always on the same network. I suppose that should not be a problem, but who knows... Even an address literal in square brackets isn't reliable: I had been testing this for a couple of weeks and I got a reject a few minutes ago: Helo command rejected: IP literal in HELO hostname (in reply to RCPT TO command) -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <http://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)
