ioiioi
2013-12-20 17:42:28 +08:00
嗯,如果能更详细点就好了,今天有空做了点研究。
实际案例:
在RB493G中使用ssh连接221.x.x.190
root@RB493G:/etc/config# conntrack -L -d 221.x.x.190
tcp 6 3597 ESTABLISHED src=192.168.44.3 dst=221.x.x.190 sport=45442 dport=22 packets=523 bytes=31905 src=221.x.x.190 dst=183.254.47.33 sport=22 dport=45442 packets=514 bytes=101605 [ASSURED] mark=0 use=1
conntrack v1.0.0 (conntrack-tools): 1 flow entries have been shown.
root@RB493G:/etc/config# netstat-nat -n -d 221.x.x.190
Proto NATed Address Destination Address State
tcp 192.168.44.3:45442 221.x.x.190:22 ESTABLISHED
root@openbsd-2/etc:# netstat -an | grep 22
tcp 0 84 221.x.x.190.22 183.254.47.33.45442 ESTABLISHED
由此看出,RB493G优先使用了45442这个源端口向221.192.254.190:22发出请求,当45442被其它connection占用后,才另行找新的源端口。