关于Extended PAT Table

百花开的

TCP PAT from inside:10.1.1.11/51550 to outside:192.168.18.90/51550 flags ri idle 0:00:15 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52062 to outside:192.168.18.90/52062 flags ri idle 0:00:06 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52061 to outside:192.168.18.90/52061 flags ri idle 0:00:27 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52060 to outside:192.168.18.90/52060 flags ri idle 0:00:28 timeout 0:00:30
UDP PAT from inside:10.1.1.12/7273 to outside:192.168.18.90/7273 flags ri idle 0:00:42 timeout 0:00:30


Use Round Robin Allocation  默认是pat到同一个址。这个端口用完了在pat到号一个地址。启用这个成了随机的。


TCP PAT from inside:10.1.1.11/14662 to outside:192.168.18.91/14662 flags ri idle 0:00:09 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52079 to outside:192.168.18.90/52079 flags ri idle 0:00:00 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52078 to outside:192.168.18.90/52078 flags ri idle 0:00:04 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52077 to outside:192.168.18.90/52077 flags ri idle 0:00:13 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52076 to outside:192.168.18.90/52076 flags ri idle 0:00:21 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52065 to outside:192.168.18.90/52065 flags ri idle 0:02:55 timeout 0:00:30
UDP PAT from inside:10.1.1.12/7273 to outside:192.168.18.90/7273 flags ri idle 0:02:55 timeout 0:00:30


Extended PAT Table
启用Extended PAT Table后.会在nat表项中纪录目的地址。转换可以越过65535表项的限制。就算你的两个不同的内部主机，转换成同一个公网地址的同一个端口号。
只要它们访问的目的主机不同，也是可以的。回包路由可以根据不同的源地址找到相应的表项。



> show xlate
4 in use, 69 most used
Flags: D - DNS, e - extended, I - identity, i - dynamic, r - portmap,
       s - static, T - twice, N - net-to-net

TCP PAT from inside:10.1.1.11/41107 to outside:192.168.18.90/41107(192.168.18.11) flags rie idle 0:00:03 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52105 to outside:192.168.18.90/52105(202.108.23.105) flags rie idle 0:00:01 timeout 0:00:30
UDP PAT from inside:10.1.1.12/7273 to outside:192.168.18.90/7273(112.80.248.135) flags rie idle 0:00:07 timeout 0:00:30
TCP PAT from inside:10.1.1.12/52104 to outside:192.168.18.90/52104(202.108.23.113) flags rie idle 0:00:17 timeout 0:00:30







Flat Port Range
正常情况下，转换后公网地址的端口号，是根据主机发出的原始端口。在转换的原始端口的对应的端口组里面选择一个。正常情况下分成三组1-511 512-1023 1024-655535













三组，默认情况下在组里面选择。也就是说假设源端口号是1025那么转换后的公网的端口号只能在1024-65535这个范围内。当打开这个之后将打破这个限制。
Include Reserve Ports
正常情况下1-1023是预留的。如果要使用预留端口的话。需要打上这个。