Solved

Web Servers not accessible due to Nat and external DNS

Posted on 2002-04-09
3
314 Views
Last Modified: 2010-04-17
we have a linux machine and an NT webserver which is visible from the outside of the organization thru NAT, using a statememt like:

ip nat inside source static tcp 192.168.1.3 80 213.147.165.130 80 extendable.

browsing the webserver from outside the org. works fine.  However, when we attempt to browse the website from machines from within the org. we get permission dialogs and authentification errors.  This is because essentially, we are trying the browse the router from the inside interface.  Ie, DNS queries for the domain and finds that 213.147.165.130 is the ip address the website is on.  It then tries to connect to this address, but thru the internal router network card.  This causes the login dialog to appear.

Is there a way to tell the router that is should redirect traffic which connects to the external network card via the internal network card on a specific port (i.e. only on port 80, 21 etc) back using the NAT settings?

Thanks

0
Comment
Question by:ossentoo
  • 2
3 Comments
 
LVL 4

Expert Comment

by:svindler
ID: 6927523
You have (at least) three options:
1)
The router will change dns replies if there is a static one-to-one nat ie:
ip nat inside source static 192.168.1.3 213.147.165.130

This is the easiest but require that you actually have a specific ip address to use for each server.
2)
Put the servers on a separate leg of the router, and make the same NAT from inside as from the outside.

This gives you the added benefit of a more secure solution, but is the most expensive.
3)
Setup an internal dns-server with the correct replies for the inside addresses.
This solution can be used in most cases but involves the most work and administrative overhead if you have more servers.
0
 

Author Comment

by:ossentoo
ID: 6931322
I've actually implemented the third solution.  However, if the linux machine which actually hosts the DNS record is switched on first, and then the webserver is switched on after some clients machines have been turned on, the clients get there DNS queries answered by the linux machine, which then informs them that the DNS record for motorsport.co.ug is 213.147.165.130.  

As the webserver is actually at a 192.168.1 address, the client fails and needs to be rebooted in order to get the correct DNS address of 192.168.1.*.  
0
 
LVL 4

Accepted Solution

by:
svindler earned 150 total points
ID: 6932475
What I meant by solution 3 was to setup a dns server on the inside that would actually respond with the 192.168.1.* address of motorsport.co.ug, whenever inside clients asked.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Tired of waiting for your show or movie to load?  Are buffering issues a constant problem with your internet connection?  Check this article out to see if these simple adjustments are the solution for you.
In the world of WAN, QoS is a pretty important topic for most, if not all, networks. Some WAN technologies have QoS mechanisms built in, but others, such as some L2 WAN's, don't have QoS control in the provider cloud.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

895 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now