On 22 Aug 2007, John Rudd spake thusly: > Nix wrote: >> My ISP doesn't give me that option (well, OK, it probably gives *me* >> that option because I can bug the ISP's technical director, but not >> people who've posted bonds). I'd venture to guess that the vast majority of >> small business UK ISPs, even those that do not provide useful outbound >> relaying >> MTAs, do not delegate rDNS to individual users. > > And they can't set one of the MX records, or A records, for their mail domain > to be the same as that of the static IP address their > static IP address? > > Because EITHER one of those things will trigger an exception for Botnet.
Oh, right, so botnot only triggers if you're sending from something that isn't an MX *and* satisfies one of the other criteria? That's sensible, and I hadn't thought of it, and I'd also brilliantly managed to overlook it repeatedly when wandering through the botnet code. (God knows how. Insufficient coffee, probably.) There are sometimes reasons for a host without an MX to send mail, but it's bloody rare outside of big clusters (i.e. not boxes fronting for little networks), and I can see no reason why anyone can't get a low- priority MX pointing at them even if they can't run an MTA on it (no harm will be done in that case, of course).
