Quoting Mark Martinec <[EMAIL PROTECTED]>: > John, > > > Hm. So, I'm sure I can figure this out eventually, but does anyone know > > the right Net::DNS way to extract the TTL? > > I don't think it is possible to obtain the original TTL from DNS responses. > > The information received in a reply only indicates a remaining time > this information has, before it need be refreshed from a source. > If responses come from a cache of a local name server, the resulting > TTL will get smaller by every call answered from a cache. Try and see!
If you query an authoritative nameserver, you get the undecayed TTL. However querying the authoritative nameserver isn't always a good idea, especially ones that belong to bad guys. They can give the wrong answers, block you, etc. They also potentially help identify your mail filter IPs to the bad guys. It's probably better to let URI blacklists like SURBL find and blacklist those domains. We're doing some of it now and will be doing more in future. Jeff C.
