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Beginner

Unable to resolve external hostname internally

Hello,

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.

Any help would be greatly appreciated!

Everyone's tags (6)
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Rising star

Unable to resolve external hostname internally

Hi Joseph,

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.

hth

MS

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Beginner

Re: Unable to resolve external hostname internally

It does - mail.example.com resolves to our public IP for the office ASA -- thanks for the response.

However, can someone elaborate more?

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Re: Unable to resolve external hostname internally

Hello Joseph,

Are you using an internal or external DNS?

also what code are you running?

Regards,

Julio

Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC
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Beginner

Re: Unable to resolve external hostname internally

Hello Julio,

Not sure on the code. Using external DNS for outside queries.

Thanks,

Joseph

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Re: Unable to resolve external hostname internally

Hello Joseph,

Please do a show version ( you will get the OS version of your ASA). Then based on that I will provide you the resolution to this,

Regards,

Julio

Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC
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Beginner

Re: Unable to resolve external hostname internally

Cisco Adaptive Security Appliance Software Version 8.2(5)

Device Manager Version 6.4(5)