terry@DEC-VAX-11-750.ARPA (03/03/88)
All, If there is an update to this, feel free to flame me, but please be gentle. ****---- Brian Lloyd, Mil-Std-1778, 12-Aug-1983, Page 92: There are two cases for the format of an option: a) A single octet of option-kind. b) An octet of option-kind, an octet of option-length, and the actual option-data octets. The option-kind field determines the option being processed. This option-kind MUST be known, otherwise there is no way to tell whether the next octet is a new option, or the length of the current option. Therefore, further option processing cannot occur. Your Question: Will this upset any TCP implementations? My Answer: YES In MY TCP implementation, an unknown option will cause a message to be placed in a log file along with all of the remaining bytes in the TCP header. If a valid option, such as maximum segment size, occurred after the unknown option the valid option would be ignored. This could be serious. I would take a guess and say that ALL TCP implementations are probably not as gracious as mine. Some probably would ignore the packet, others might curl up and die, or worse. *****----- Non-TCP-Related-Topic: There is a place for copy protection schemes in the world. However, your scheme only prevents your TCP from talking to itself, not to other TCP implementations. Besides the problem I stated above, it seems to me that if you want to copy protect your software, do it right. Don't do it halfway. There are several methods of controlling software execution available. Pick One. If your company doesn't have the people to do the job, hire someone. ****---- Terry Robb
STJOHNS@SRI-NIC.ARPA (03/03/88)
Terry, Jon Postel has decreed that for both TCP and IP, any additional options will be of the second type... I.e. self encoding the length. Mike