源端口号——源计算机为TCP或udp分配的端口号，例如，1080。

Source port-the TCP or UDP port number assigned by the originating computer for this packet, for example, port 1080.

youdao

由于nat路由器现在已经拥有了这台计算机保存在地址转换表中的的源地址和源端口号，它将会在有效期内继续使用同一个端口号进行转换。

Since the NAT router now has the computer's source address and source port saved to the address translation table, it will continue to use that same port number for the duration of the connection.

youdao

然后它用它自己注册的IP地址替换发送来的数据包的IP地址，并将端口号替换为该数据包的源计算机信息条目在表中的相应位置号。

It then replaces the IP address with its own registered IP address and the port number corresponding to the location of the entry for that packet's source computer in the table.

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