Hi All... Ok, DNS is a strange beast at best.
One of the main problems I have found, is people having TTLs of 0 seconds. Effectively the query has timed out before it has returned. This does not seem to be the case in the mentioned domains, i.e. ifrance.com etc. It does make sense about what Rob said, about the DNS being "slow", and it ending up with an A record. Our DNSCaches are actually configured to do minimal answers, which would trigger such a problem. I have however not see that yet. What you want is to have your dnscache returns as much data on the same as possible. However, I am not sure how XMail will deal with that. Being a legacy definition, new mail servers should actually never look up the A record. This is so by the way a huge favourite of spammers. Our domain used to have an a record, and I had a server sitting on it, accepting ALL mail for our domain, and basically it was 99.999% spam. The 1 in 10000 that was valid can kiss my backside... We therefore removed the A record. Normally it would be better to ensure that the server the a record points to, does not answer on SMTP, or rejects connections. (Network error, forcing retry...) Again, I am not sure if XMail actually re-looks at the DNS before sending email, or does it look at it's own records, i.e. the A-record. In practicality, the MTA should re-query the DNS every time it tries to send it. Therefore, fancy "nice to have" feature would actually be a server config, which specifies if the server should "fall back" to A record delivery, or not. However, this might be counter-RFC's for all I know... I do believe to put a local DNS caching program on our mail servers, to alleviate issues like over-expiry etc. Your server's cache would be more specific to it's own environment, as well as the Hosts connecting to it, and being connected to. (Streamline cache content.) You could possibly also tweak the local DN server to your needs, i.e. lengthen/shorten negative expiry, and possibly even tell it to not lookup A records on domains... (Might be tricky, as you need to look up the A record for the mail server...) The one I like to use is PDNSD, which I am not sure if there is one for the windows platform. The beauty about this one is the fact that it saves its cache to disk on shutdown, and reloads it again on startup, allowing for quick startup times. Homepage for PDNSD: http://www.phys.uu.nl/~rombouts/pdnsd.html -- Best regards, Jorn mailto:[EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
