SYN - - "" .
, TCP/IP . C-SYN- S-SYN/C-ACK -, SYN_RECEIVED . S-ACK, , ESTABLISHED.
, , SYN -, . RFC .
SYN - , . - Panix, - . Panix 2- .
. , BSD-, 16 . SunOS, , . , , , , WWW- BSD 16 SYN-, Solaris 2.5 .
( ) . . , 2400 bps, 20-30 FreeBSD-, (, FreeBSD).
, IP- , .
- SYN_RECEIVED, . , "" . , , SYN-, .
- firewall , TCP/IP- , . SYN- .
, . , , telnet ftp. , .
, ( "SYN-ACK") . NT 3.5-4.0 5 - 3, 6, 12, 24 48 . 96 , , . - 189 .