This article is from the FAQ, by with numerous contributions by others.
Depending upon the version of WinTalk you use, you may either:
1) have trouble running the program, with frequent "gethostname()"
or similar error messages, or
2) the program may appear to work properly until you attempt to talk
with someone, and you receive a "They don't recognize us!" error.
The solution depends upon the way you're accessing the Internet. If
you're not sure which the of the below you're using, ask your provider
If you're on a SLIP or PPP connection with a permanent IP Address:
Your machine may not be listed in your provider's DNS. Ask your
provider to add it. If your account is new, keep in mind that it
may take several days before your machine name is in the DNS, at
which point WinTalk should work properly.
If you're on a SLIP or PPP connection with Dynamic IP Addressing:
It's very likely that some, if not all, of the IP addresses in the
dynamic IP pool are not registered in the DNS. Ask your provider to
please do this, if possible.
Emulated SLIP (TIA, etc.):
WinTalk is incompatible with emulated SLIP. Sorry, there are no
workarounds at this time.