SSH连接超时不自动断开

Posted 2020-06-14

 

Putty

 

　　启用putty keepalive

 

　　putty -> Connection -> Seconds between keepalives ( 0 to turn off )，默认为0，改为60。

 

更改ssh服务器的配置文件/etc/ssh/sshd_config

 

　　ClientAliveInterval指定了服务器端向客户端请求消息的时间间隔, 默认是0，不发送。而ClientAliveInterval 60表示每分钟发送一次，然后客户端响应，这样就保持长连接了。这里比较怪的地方是：不是客户端主动发起保持连接的请求(如FTerm, CTerm等),而是需要服务器先主动。

 

　　另外，至于ClientAliveCountMax，使用默认值3即可。ClientAliveCountMax表示服务器发出请求后客户端没有响应的次数达到一定值，就自动断开，正常情况下，客户端不会不响应。

 

　　ClientAliveCountMax

 

　　Sets the number of client alive messages (see below) which may be sent without sshd(8) receiving any messages back from the client. If this threshold is reached while client alive messages are being sent, sshd will disconnect the client, terminating the ses-sion. It is important to note that the use of client alive messages is very different from TCPKeepAlive (below). The client alive messages are sent through the encrypted channel and therefore will not be spoofable. The TCP keepalive option enabled by TCPKeepAlive is spoofable. The client alive mechanism is valuable when the client or server depend on knowing when a connection has become inactive.The default value is 3. If ClientAliveInterval (see below) is set to 15, and ClientAliveCountMax is left at the default, unresponsive SSH clients will be disconnected after approximately 45 seconds. This option applies to protocol version 2 only.

 

　　ClientAliveInterval

 

　　Sets a timeout interval in seconds after which if no data has been received from the client, sshd(8) will send a message through the encrypted channel to request a response from the client. The default is 0, indicating that these messages will not be sent to the client. This option applies to protocol version 2 only.

 

　　vim /etc/ssh/sshd_config

 

　　找到ClientAliveInterval 参数，如果没有就自己加一行。

 

　　ClientAliveInterval 参数的数值是秒，比如你设置为540，就是9分钟.

 

　　ClientAliveInterval 540

 

　　对于ClientAliveCountMax

 

　　指如果发现客户端没有相应，则判断一次超时，这个参数设置允许超时的次数，比如10。

 

　　ClientAliveInterval 540

 

　　ClientAliveCountMax 10;

 

　　则代表允许超时 5400秒 = 90分钟。