Problem solved: I finally managed to get both the proxy-app and server-app run on the same host by placing the server app into a linux container (LXC) on the same host and using a bridge (br0) for the container(s). The server-app (currently a test app) sends this msg: hello to client 5.199.129.129:57456 from server 10.10.20.2:8847 via proxy 37.139.71.2:8846 Previously the host had the IP 192.168.68.22, then I experimented with public IPs behind NAT :-), so since now the 37.139.71.2 works I'll let it so. This IP belongs to someone else in Australia, but it IMHO doesn't matter because I'm using it inhouse behind NAT... :-) for testing only. The 5.199.129.129 is one of my own public IPs (mutluit.net). The test client sits there. If I find time I'll repeat the test with the 192.168 adress, but not now... :-) Phew.. this was a prohibitly hard & expensive job... took me about a week to finally come to this f..ing solution... :-) cu Uenal