On 7/30/2009 10:51 AM, Noel Jones wrote: > Address verify callouts are quite time consuming, so quite expensive - > much more than an RBL lookup. However, when valid recipients are found > in the cache, the impact on mail should be very low.
Thanks for correcting me... that is good to know. > So using a cache with a generous positive expire time is a very good idea. Good idea/point. >>> Also I want to use the address_verify_map cache and want it to be as >>> small as possible. >> You could set address_verify_negative_cache = no, to limit it to only >> caching positive hits. > Probably better to just set negative caching to a small time limit - > maybe a few hours. Another good idea/point. > You're right that doing sender verification on all mail will eventually > get you blacklisted. Doing recipient validation will only get you > blacklisted if your own users do a directory attack on some third party > - but that will get you blacklisted whether you do validation callouts > or not... Right, forgot about the distinction... thanks for the clarifications Noel... > That said, recipient verification only makes sense for domains > you relay and don't have a valid recipient list for. Which is the situation for the OP... -- Best regards, Charles
