Here is what I get using the same settings except for K4 address.

Thanks that helps. I downloaded the updated rig control file and it has the K4 commands correct as you show. I can control with the rig with a Com port but not TCP.

Understand. Definintely not a firewall issue. I am trying to use as few com ports as I can. Actually the name will translate to a vallid address per mDNS. See ping below. Unfortunately some software like N1MM and apparently VarAC still require a hard coded ip. Other like WSJTX, DXLog.net HamLib and many others follow the standard.

Tried Anan Thetis and Smart SDR (Flex) did not work at all. Did some more testing and found that TCP to K4 with IP address only works some of the time. If I use K4 with a comm port it works with no trouble. If I use TCP with a host name "K4-SN01280" which is how I do it in WSJT-X I get the following error. Omnirig is not working any more though it works fine in Log4OM and WSJTX. I get the folllowing error. Here is a summary.

Screen shots of working WSJT-X config and VARAC PTT working with Omnirig but not working with Elecraft This works in WSJT-X for frequency change and PTT This works for VarAC frequency control but not PTT This works for VarAC frequency control and PTT but obviously requires Omnirig. Thanks. Joe AF1E