SO_KEEPALIVE timer

[Teh Kok How <khteh@willowglen.com.my>]

Hi;
	In windows and solaris, the tcp will time out when the connection is lost for 
20 minutes. 
	In OpenBSD I try to modify TCPTV_KEEP_IDLE in tcp_timer.h and test out using 
telnet session but unfortunately telnet does not sosetopt the SO_KEEPALIVE 
flag. This means that tcp_keep_timer() routine has no way to check if the 
connection is still valid after TCPTV_KEEP_IDLE and drop the connection if it 
is not. My question is should this connection check be done in the tcp timer 
code or in the link layer (mii or ethernet driver) should do the check and 
inform the TCP to drop the connection..?
	Any comment and insight is appreciated.

Regards,
TEH