How to redirect request for specific domain to a specific web application listening on a specific port?

Question

I have apache2 running on the port 80 and other application server running on 81.

I would like to redirect traffic only for one specific, selected domain (mydomain.com) to server running on the port 81 and access this website like http://mydomain.com/

I added iptables rule:

iptables -A PREROUTING -t nat -i eth0 -p tcp -d mydomain.com -j REDIRECT --to-port 81

but unfortunately not only this selected domain have been redirected, but also all other websites running on port 80 and apache2 that shouldn't be redirected to port 81.

Is there any solution to achieve only one selected domain redirection to another port?

Any help would be highly appreciated.

Answer 1

You can configure it from apache using NameVirtualHost directive and additional ProxyPass and ProxyPassReverse directives provided by mod_proxy module. Here is a basic configuration.

NameVirtualHost *:80

<VirtualHost *:80>
ServerName mydomain.com
DocumentRoot /var/www/mydomain
ProxyPass / http://localhost:81/
ProxyPassReverse / http://localhost:81/
</VirtualHost>

<VirtualHost *:80>
ServerName www.mydomain2.com
DocumentRoot /var/www/mydomain2
</VirtualHost>

Answer 2

iptables cannot see HTTP host headers.

What you'll want to do is either an HTTP redirect from Apache (telling the client to look at http://mydomain.com:81/) or reverse proxying from your port 80 Apache to the port 81 application (the client's URL won't need to change, but all traffic will be passed through Apache, adding additional overhead).

Answer 3

First, the use of DNS names in iptables rules is discouraged. Iptables will lookup the name only once at the beginning and the retrieved IP will be used instead of the name. So, avoid using DNS names in iptables rules.

Second, you can do this using iptables only if you have a different IP address for each domain you want to distinguish (redirect) to another port. Otherwise, you need to use other ways such as: reverse proxy, redirection, etc...