hi. i've been toying with using sendmail/spamassassin on a linux box placed in front of our exchange server to do our spam filtering. i've received some very helpful help (a bit redundant?) from a listee member. however instead of continuously bugging him, i thought i'd come to the list for some ideas and maybe some pointers. what i've done so far is take a computer home from work (an old hp that's been lying around) and set it up on my home network which is connected to teh intarweb via dsl. (the member i spoke about earlier even went so far as to give me a temporary domain for testing purposes.) i've got redhat 8 installed with sendmail and spamassassin working properly. here are my problems. 1. i'm not sure what DNS changes need to be made at our isp (earthlink) so that i can properly integrate the computer for testing purposes and/or production. i'm confused by the whole MX record thing. let me explain why i'm confused... our domain for this example will be domain.com (how original!). that makes our webserver at domain.com and www.domain.com, our email server (the exchange 2k box) is at mail.domain.com. when someone sends mail to user at domain.com (somewhere along the line) it is found out that mail should be directed to the computer lying at mail.domain.com correct? if that is the case (which indeed i believe it is) what would i need to change to have the mail be sent to the linux box? would i need to register the linux box as mail.domain.com and make the exchange box something else, like exchange.domain.com? 2. i've been using the virtusertable file to forward mail while i've been making my tests. however this has the unfortunate side affect of changing destination domains. for example if i send an email to chris at mytestdomain.friend.com i can forward it to my hotmail address. what i found out later is that i need to use the mailertable instead of the virtusertable to avoid this problem. however i can't seem to do this because i think the DNS records need to be setup properly first. having said all that, i'd appreciate any links/hints/help that you could offer me while i try to get this thing done. thanks a lot!!! chris.