I was unable to bind the client to the 10.1.1.2 address. Unfortunately I've been only able to use this option to bind the server to the 10.1.1.1 address. There is also the IPERF tool which has the -B option. How do I specify these addresses in TTCP? These are the IP addresses assigned manually to each network adapter. I want 10.1.1.1 to be the server (receiver) and 10.1.1.2 to be the client (transmitter). But why does it say 0.0.0.0? Is it passing through only one of the network adapters? Send Mode : Send Pattern Number of Buffers: 2048 On the transmitter end: C:\PCATTCP-0114>PCATTCP.exe -t 10.1.1.1 PCAUSA Test TCP Utility V2.01.01.14 (IPv4/IPv6) On the receiver end: C:\PCATTCP-0114>pcattcp -r They're giving me hard time because I'm using the same physical PC. I'm trying to do a simple loopback test between the two. They function as two separate network adapters.