smmapd over TCP port

[Steven Ingram]

I'm trying to setup smmapd to listen on a TCP port as sendmail is on a
different system than cyrus-imap. I tried adding the line:

smmapd       cmd="smmapd"  listen="imap1.4test.net:smmapd" prefork="1"

to the cyrus.conf file only to be greeted with the error:

Jan 19 00:45:27 imap1 master[21511]: Servname not supported for
ai_socktype, disabling smmapd

According to the source file smmapd.c, there is a way to do this, I'm
just not sure how. Is this possible?