# &faqguide;

After switching to OpenSIPS 2.1, I'm getting this error: "listeners found for protocol tcp, but no module can handle it"

You need to load the "proto_tcp" module. In your script, make sure you do a loadmodule "proto_tcp.so" after setting the mpath.

I cannot locate "proto_tcp.so". Where is it?

The "proto_udp" and "proto_tcp" modules are simply built into the opensips binary by default. They are not available as shared libraries, but look like modules for code consistency reasons.