DNS - 1 IP

[Doyley3731]

Hi all,

Bit of a noob to DNS.

We have two webservers on our internal network. Their internal addresses are 192.168.1.110 and 192.168.1.111.

We have one external IP address which is routed to our firewall.

In our firewall I have told it to forward any HTTP requests to 192.168.1.111. On that server I also have DNS software running. On that I have said that if the domain is example.com to send it to 192.168.1.110 with A records but it isn't working. Is it correct what I have done?

Thanks!

 

[elgrandeperro]

First, DNS is port 53, not http port 80. You need to port forward DNS packets (both tcp and udp, port 53) to your DNS server.

Then to get a web server working, you need to port forward HTTP packets to your web server. Then advertise the single external IP address, the A record as

http://www.example.com.

 

[Doyley3731]

Thanks for your reply.

Yes I know about DNS on 53, I have already configured the firewall for this. I should have mentioned that in the post.

The firewall is currently sending DNS and HTTP to 192.168.1.111. For certain sites I need the HTTP request to be sent to 192.168.1.110.

So for example. example1.com is hosted on 192.168.1.111 but example2.com is hosted on 192.168.1.110

If I try to go to example2.com now it doesn't work because it is trying to connect to 192.168.1.110 from outside the LAN but example1.com works.

Is this possible to fix with DNS or will I need to get a new external IP for 192.168.1.110?

Thanks

 

[elgrandeperro]

Since you are hiding behind a single IP, it would be way easier if both web sites were on the same box so you could use named base virtual hosting.

If on separate boxes, I believe you could create one as both a web server and reverse proxy for the other.

The other option is to port forward a non-port 80 port like 81 to one of your sites.

 

[lhuegele]

I don't understand why you need some DNS requests to go to one server and others to go to a second server, but most firewall setups don't let you forward ports to more than one destination address.

If you need to have 2 externally facing DNS servers, you will need a seperate external IP address for each one. That way you can forward traffic to both over the same port depending on which external IP the request came in on.

Good luck,

 

[theravager]

This isn't possible to fix with dns.

 

[paella33]

Microsoft has NLB (network load balancing). If you are running IIS, you could use that. Other OSs can use similar technology.

 

[Doyley3731]

Thanks guys.

It is for a client who has just bought these servers, I'll convince him to use one as a DB server or something.

Thanks again!

 

[elgrandeperro]

Uhhh, I am not familiar with that type of LB, but if it doesn't inspect the HTTP request for the URL it will not work. It might only work at the TCP/IP level.

If you clustered the web sites and virtual hosted them, then you could use the LB.