We help IT Professionals succeed at work.
Get Started

Can Cisco resolve internet address internally

jgrammer42
jgrammer42 asked
on
137 Views
Last Modified: 2017-01-10
Here is the situation.  I have an internet domain of CORPORATION.COM

Exchange is the mail server with the DNS name of MAIL.CORPORATION.COM on the internet.

MAIL.CORPORATION.COM is used by laptop, (for example), for Outlook Anywhere access.

MAIL.CORPORATION.COM resolves to internet address of 200.250.192.100  (again, just an example)

My Cisco ASA NAT's the external IP of 200.250.192.100 to the internal LAN address of 192.168.1.50

All of that works great.  No problems.

However, when someone with a laptop comes into the corporate office, and tries to resolve the name of MAIL.CORPORATION.COM,  the internet DNS responds with 200.250.192.100 which the Cisco is unable to resolve or map back to the internal network of 192.168.1.50, which is the Cisco's internal known IP network.

For years, the way around this is to set up on the INTERNAL LAN DNS a CORPORATION.COM domain, that all local LAN clients would use to resolve back to the internal LAN network of 192.168.1.y, instead of to an external Internet address.

Frankly, I HATE that solution.  I always thought it was kludgy at best.

So, the question is this, is there a way to configure the Cisco that if it sees an internet address that maps to its known internal LAN network IP, it will automatically respond back with that internal LAN address instead of just getting stuck in a loop?

Thank you in advance,
Jeff
Comment
Watch Question
Network Architect
CERTIFIED EXPERT
Top Expert 2014
Commented:
This problem has been solved!
Unlock 1 Answer and 4 Comments.
See Answer
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE