gotables is a very simple replacement for iptables for simple port forwarding. It listens on a given host and port and pipes all traffic to a remote host and port.
go get github.com/beatgammit/gotables
The configuration file format is a very simple space-delimited format of <src> <dest>. For example, the following will forward all traffic received by the host (the computer gotables is running on) on port 10000 to 192.168.1.100 on port 20000:
# forward all traffic from port 10000 to 192.168.1.100 on port 20000
0.0.0.0:10000 192.168.1.100:20000
Comments consist of a leading #, as above.
gotables is licensed under the BSD 2-clause license. Please check LICENSE.BSD for specifics.