here is the thing...on ur DNS all the A records will be for global ips not private ips. If some 1 from outside comes to ur DNS to c MX record it should c a global ip. Now for internal users there is two things u can do either use a host file on each machine so everytime it tries to go to mailserver it should come with private ip or put nother internal dns and have the host names with local ip addresses. u can make this internal dns as forwarder only so for all internal user this is the only dns server , even to go out. and external dns with global ip mapping i.e address records being only for outside users. that is how i m doing on my network. if there is ne better way guyz let me know...but it works for me
As of BIND 9.0 (and I think 9.1.1rc1 was released a day or so ago) you can do this with one DNS server and multiple "views". You can make an inside "view" and and outside "view". Then using pretyy simple ACL syntax, you define which address spaces see which view. You can then make all your internal addresses see the inside view and everyone else see the outside view.
Of course, we do our split DNS the old 2 server way for other reasons, but if you only have one machine to spare, this is a good option.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...