|
|
楼主 |
发表于 2022-3-15 14:29
|
显示全部楼层
https://cloud.tencent.com/develo ... icle.detail.1025062
https://www.thegeekdiary.com/hig ... tat-command-output/
BOUND
Bound, ready to connect or listen.
CLOSED
Closed. The socket is not being used.
CLOSING
Closed, then remote shutdown; awaiting acknowledgment.
CLOSE_WAIT
Remote shutdown; waiting for the socket to close.
ESTABLISHED
Connection has been established.
FIN_WAIT_1
Socket closed; shutting down connection.
FIN_WAIT_2
Socket closed; waiting for shutdown from remote.
IDLE
Idle, opened but not bound.
LAST_ACK
Remote shutdown, then closed; awaiting acknowledgment.
LISTEN
Listening for incoming connections.
SYN_RECEIVED
Active/initiate synchronization received and the connection under way
SYN_SENT
Actively trying to establish connection.
TIME_WAIT
Wait after close for remote shutdown retransmission.
'CLOSE_WAIT' state means the other end of the connection has been closed while the local end is still waiting for the application to close. The local end-point has received a connection termination request and acknowledged it e.g. a passive close has been performed and the local end-point needs to perform an active close to leave this state.
CLOSE_WAIT indicates that the remote endpoint (other side of the connection) has closed the connection.
TIME_WAIT indicates that local endpoint (this side) has closed the connection.
Details
‘CLOSE_WAIT’ state on tcp connections occurs if the system has not received a close system call from the application, after having received notification (‘FIN’ packet) from the other system that it has closed its endpoint. In other words it means that the local end of the connection has received ‘FIN’ from the other end, but the OS is waiting for the program at the local end to actually close its connection.
The problem is that a program running on the local machine is not closing the socket. It is not a TCP tuning issue. A connection can stay in ‘CLOSE_WAIT’ forever while the program holds the connection open. So mostly this issue happens due to an application bug. However if TCP/IP parameters are not properly set, closed TCP/IP connections will stay for a very long time in various ‘CLOSE’ states which take file descriptors from the process. In order to solve this problem, sometimes it is necessary to tune TCP/IP parameters, so that TCP/IP connections are closed in a short amount of time.
修改Time_Wait参数的方法 (在服务端修改，需要重启机器)
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "TcpTimedWaitDelay" /t REG_DWORD /d 30 /f
＜2012R2和Win8.1的系统，执行：
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "TcpTimedWaitDelay" /t REG_DWORD /d 30 /f
≥2012R2和Win8.1的系统，执行：
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "TcpTimedWaitDelay" /t REG_DWORD /d 2 /f
Key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Value:
TcpTimedWaitDelay
Data Type:
REG_DWORD
Range:
Windows Server 2012 and earlier: 30-300 (decimal)Windows 8 and earlier: 30-300 (decimal)Windows Server 2012 R2 and later: 2-300 (decimal)Windows 8.1 and later: 2-300 (decimal)
Default value:
0x78 (120 decimal)
Recommended value:
30
Value exists by default?
No, needs to be added.
Close_Wait引发的问题：
Close_Wait数量过多会引起网络可用连接少、网络性能下降，并占用系统非换页内存。 尤其是在有连接池的情况下(比如HttpRequest)会耗尽连接池的网络连接数，导致无法建立网络连接。
解决CLOSE_WAIT的方法:(在客户端修改)
分析：
1、一般原因都是TCP连接没有调用关闭方法。需要应用来处理网络链接关闭。
2、对于Web请求出现这个原因，经常是因为Response的BodyStream没有调用Close
比如Widnows下：
使用HttpWebRequest 一定要保证GetRequestStream和GetResponse对象关闭，否则容易造成连接处于CLOSE_WAIT状态。
3、TCP的KeepLive功能，可以让操作系统替我们自动清理掉CLOSE_WAIT的连接。
但是KeepAliveTime在Windows操作系统下默认是7200秒，也就是2个小时才清理一次，往往满足不了需求，可以调小该数值。
Windows下的调整方法为
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]下的以下三个参数：
KeepAliveTime,设置其值为300000(单位为毫秒，300000代表5分钟)
KeepAliveInterval,设置其值为1000(单位为毫秒，1000代表1秒)
TcpMaxDataRetransmissions，设置其值为4
具体执行：管理员身份运行如下命令(重启生效)
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "KeepAliveTime" /d 300000 /t REG_DWORD /f
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "KeepAliveInterval" /d 1000 /t REG_DWORD /f
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "TcpMaxDataRetransmissions" /d 4 /t REG_DWORD /f
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "TcpTimedWaitDelay" /t REG_DWORD /d 2 /f
reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" /v "TcpMaxConnectRetransmissions" /t REG_DWORD /d 2 /f
或者以下另存为close_wait.reg导入系统即可(重启生效)
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
"KeepAliveTime"=dword:000493e0
"KeepAliveInterval"=dword:000003e8
"TcpMaxDataRetransmissions"=dword:00000004
"TcpTimedWaitDelay"=dword:00000002
"TcpMaxConnectRetransmissions"=dword:00000002
参考资料：
KeepAliveInterval
https://docs.microsoft.com/en-us ... 000-server/cc957548(v=technet.10)
KeepAliveTime
https://docs.microsoft.com/en-us ... 000-server/cc957549(v=technet.10)
TcpMaxConnectRetransmissions
https://docs.microsoft.com/en-us ... 000-server/cc938209(v=technet.10)
TcpMaxDataRetransmissions
https://docs.microsoft.com/en-us ... 000-server/cc938210(v=technet.10)
TcpTimedWaitDelay
https://docs.microsoft.com/en-us ... 000-server/cc938217(v=technet.10)
EnableDeadGWDetect
https://docs.microsoft.com/en-us ... 000-server/cc960464(v=technet.10)
https://www.ibm.com/support/page ... p-keepalive-windows
https://community.progress.com/s ... -IP-Port-Exhaustion
统计closewait的powershell命令
(get-nettcpconnection -state closewait).count
(netstat -ano).count
cmd下netstat -ano|find /c "CLOSE_WAIT"
原创声明，本文系作者授权云+社区发表，未经许可，不得转载。
如有侵权，请联系 yunjia_community@tencent.com 删除。
云服务器Windows ServerWindows |
|
发表于 2022-3-10 16:07