8093 is open as a TCP port and I can connect to it from the other container. However, 18093 is not open from the remote container nor from within the couchbase container itself. This is what’s listening on in the couchbase container, and these are all able to establish a connection from the remote container (I just checked each port):
tcp 0 0 0.0.0.0:11209 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:11210 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9100 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:21100 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9101 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9102 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9999 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:21200 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9105 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:4369 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:21300 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:8091 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:8092 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:8093 0.0.0.0:* LISTEN -