Hello! Finally I signed up, since the howtos here helped me alot! I want to "edit" the source ip of my outgoing dns traffic(packets): Client (IP:22.214.171.124) -> My DNS Server (10.10.10.10) -> External DNS Server (126.96.36.199) DNS Packet (source ip 188.8.131.52) -> My Server (magic happens) -> External DNS (source ip 10.10.10.10) So the client requests a domain from my dns server, here I want to forward the request to an external server, which checks the source ip of the request to give access. So I need to manipulate the DNS Packet to have the DNS Servers IP (10.10.10.10) as Source IP... I found the following: http://www.blissend.com/node/7 I have bind running, which will forward the requests to the other dns server, now I only need to edit the outgoing traffic on udp/tcp 53 to have the source ip of the server, right? How can i realize this with iptables? Thank in advance!