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Traffic goes from ASA & comeback on same problem


My internet link is connected on Internet Router & below downwards Cisco ASA 5520 is connected.ASA is connected with core switch cisco 4510 on downwards.

our webbased mail url is hosted outside.

Lets suppose ISP pool is owa server is Static natted on ASA with my machine traffic is going to internet with same ISP with the help of PAT on Cisco ASA & internet is working on my machine. if i want to access or ip base for mail access, its not working & also it is not pinging. i suppose to ASA is blocking for returning traffic.

is there any way to traffic will go via same Firewal & comeback on same firewall port?

Please help us how to resolve it.


Vinod Kumar Gupta


Super Bronze

Re: Traffic goes from ASA & comeback on same problem


What I understand from your post the situation is the following

  • You have a mail server on your inside network
  • Its NATed to a public IP from your ISP
  • The public IP has DNS name of associated with it
  • You are connecting to the mail server from your inside network with the DNS name?

If this is the case can you please provide me with the following information

  • the "static" command for the mail server (you can leave out the actual IPs if needed)
  • Is the DNS server you local computer uses located in the Internet or your local network?

I think you will need the ASA to handle the DNS replies that are coming from a DNS server from the outside network

This would require that you have a "dns" parameter in your "static" nat command for the mail server.

For example likes this (presuming you are running software 8.2 or earlier):

static (inside,outside) x.x.x.x netmask dns

If you are running 8.3 or newe software the same would be

object network MAIL-SERVER

host x.x.x.x

nat (inside,outside) static dns

Hope this helps.

Please rate if it was any of any help

- Jouni

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