mojombo/proxymachine — pull request #12 by truekonrads (2012-09-07 12:48:13+00:00)
Title: Localbind

The use case for these patches is a socks/tcp server on multi-homed host. This proxy must set the source IP to the same IP as where it's client established connection to.
The pacthes introduce two new arguments to proxy block - source IP and source port as well as two new options that a proxy block can return - bind_addr and bind_port.