Adam Dawes wrote:
Yes, that was part of the plan, to point my mx records to my provider. Therefore, any connections to my port 25 should be from only folks that are port scanning (sounds like a spammer to me). Think this is best done as a firewall issue or via David's host_reject option?Depends on what logging you want (or more precisly where you want it logged) and the load you can handle. Also perhaps how often and how many other connections you will want to allow (if any).thanks, Adam Dave Watkins wrote:Configuring Exim to do this would seem like a bad idea, in that your machine then has to accept a connection to determine if you do in fact even want to accept the mail. Ideally you would get the MX record for your domain pointing to your providers mail server (with perhaps a backup MX pointing to yours. That way under normal conditions mail will be routed through your providers mail servers unless they are down, and if they are down it will be routed to you. This will probably require some configuration changes on your providers servers but nothing major (just a routing line in a config file).The other option would be to firewall off port 25 for inbound traffic unless it came from your providers mail server, although this is much less elegantDave
If you want to log all the failed connections and don't want another log to go through to see who's trying to connect then obviously letting exim do it would be preferable, this is assuming your machine can handle the load of spawning exim processes for no real purpose other than logging but I don't think that would be a problem. This would also be better if you want to allow some server(s) to connect directly otherwise you will have to maintain firewall setup that will get more and more complicated as the number of allowed hosts increases.
If you're not concerned about logging or are happy to log to another file, and you won't be recieving mail from anyone other than this single host then a firewall would probably be the better option.
Dave
Adam Dawes wrote:Hi,I've implemented a spam service where a provider is filtering all my domain's mail before it hits my server. I want to lock down my mail server so it only accepts mail from those machines to prevent spammers from mailing directly to my host and doing directory harvests.What do I need to stick in my exim.conf to accept mail from just those hosts that will be processing my mail?thanks, Adam