I am working on adding a mapping to our external address for our mail server - let's call it mail.example.com
I would like to be able to access mail.example.com internally for our user's smartphones - if they access our company WiFi they are not able to get mail using the mail.example.com as the server name in their phone setups. However, once they leave the office and use any other WiFi it works fine. Also, I am unable to ping that address from any internal device. I believe also this is the reason Exchange accounts do not work on our site to site VPN connections.
I have a ASA 5520 and work primarily in the ASDM 6.4 to do configurations in the main office and have 5510 in our site to site connections.
I guess mail.example.com resolves to external IP. So the company WiFi goes thru the same ASA as your mail host connected to? If so, you may need DNS doctoring. Based on ASA version check for DNS doctoring docs.
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...