PD TCP/IP for Microport 386 v3.0e

[debula]

Does anyone out there know of a Public Domain version of TCP/IP which
works under Microport Sys V/386 v3.0e?  I am particularly interested in
acquiring a version known to work reliably (but given the price I might
settle for less).  Failing a PD version, does anyone know of an inexpensive
TCP/IP (other than Microport's, I already have heard about that).  Thanks
in advance for any help you may be able to give.