Great news everyone. I got a couple of spare hours yesterday and fixed the bugs with the TCP socket connections. As it turns out Particle's IPAddress.raw().ipv4 function was returning the IP address array in reverse order so for instance if the IP address was 192.168.0.1 this function would return array:
ip = 0x01
ip = 0x00
ip = 0xA8
ip = 0x0C
The Wiznet library classes expect the address in the reverse order so this reeked all kinds of havoc on the library. I reversed the IP everywhere needed and everything seems to be working correctly now. @aruangra I believe you were doing some testing with the library. You can pull in the latest version of my Wiznet W5500 Particle library here and give it a go if you like:
Since this is now fixed we will be releasing the Ethernet Overlay shortly. @shanevanj, @sddw, @tommy_boy, if you are interested let me know and I will ping you as soon as they hit the store.