>> Maybe I'm missing something. Can I take one of my IP addresses and make >> the RDNS appear to be from xxx.amd.com and make a lookup on xxx.amd.com >> agree? > > Yes you can. That's why reverse DNS information is pretty much completely > useless when doing any type of tracing. I suggest you read up on DNS > servers and how zonefiles work et al before going too far on speculations > regarding DNS, especially if you're using the results to filter stuff > (email > in this case).
Minor self correction here... quoted more than I wanted comment on :P You won't likely be able to make the forward lookup on amd.com agree with your faked reverse DNS, but I won't say it's not impossible either. On a separate note - if you're getting in to doing this much "dns work" just trying to figure out if a message is spam or not - I'd like to mention that DNS resolution either forward or reverse can "hang" for quite a while before it returns a result from an authoratative server. Too many lookups and you might be spending more time processing DNS info to figure out what a simple local scan of the message might easily tell you with other methods. Just a thought. Eli. -- ## List details at http://www.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://www.exim.org/eximwiki/
