RETS Server port vs no port

sdmls-rets.connectmls.com/server/login goes to a pool of rets servers and those services most vendors very well.  There are occasional rets vendors (very rare, only a few per market we service). that are using client tools that do not compute Session or Cookie headers.  Without those headers, system can’t send the subsequent requests to the appropriate server in the pool.  Having 6103 in the address ensures that the vendor’s request goes to the same server in the pool.  Our recommendation is to use the URL without the port number as that ensures redundancy on their requests, and only use 6103 when their client tools aren’t built for sessions.