Bypassing syslog by not detaching from terminal(option -d),
it is silent while there is traffic or segfaults.

With various traffic:
tcpspy -d -p                                            : no output
tcpspy -e ' not raddr 195.210.91.83' -d         : no output 

tcpspy -e ' raddr 195.210.91.83' -d
other tty:   telnet 195.210.91.83 80        -----> tcpspy segfaults