My client tried to connect twice. The proxy tried to connect a number of times and received several responses, but forwarded none on to my miner.
If you can save a pcap file and email it to me, maybe I could have a look and see what's going on.
I wonder if there is an issue here: this server has two IPs on the same subnet. Is there a way to prioritize your proxy to choose one of them exclusively? I'm afraid it's expecting an answer on eth0 but receiving one on eth1 and not properly handling it.
The kernel should take care of routing stuff correctly. If traffic is coming back on the wrong interface, that would be a problem with an upstream router and not any particular configuration on your box. If you can load other websites fine then the network config shouldn't be interfering.