TCP 508 xvttp
TCP 509 snare
TCP 510 FirstClass Protocol
TCP 511 PassGo
TCP 512 Remote process execution
TCP 513 Remote Login
TCP 514 Remote Shell
TCP 515 spooler
TCP 516 videotex
TCP 517 like tenex link but across
TCP 518 talkd
TCP 519 unixtime
TCP 520 extended file name server
TCP 521 ripng
TCP 522 User Location Service / ULP
TCP 523 IBM-DB2
TCP 524 NCP
TCP 525 timeserver
TCP 526 newdate
TCP 527 Stock IXChange