Is it possible to filter with nat rules that I can access two servers on different IP's but with the same port?
I dont think so. When somebody tries to connect to your dyn-dns server, the ip will be resolved and a tcp threeway handshake comes in place in order to establish a connection to the httpd. In this very moment there is no information in the pakets for whom the request is for (servera or serverb is not mentioned by domain name there) and the firewall has no possibility to decide where to route to. You can setup httpd to provide multiple domains by "VirtualHost" settings. Put the two servers into a cluster to loadbalance the requests to both of them. [1]http://www.linuxvirtualserver.org/ [2]http://www.backhand.org/mod_backhand/ the bob -- http://www.hs-pongratz.de