What is the value of TCP's MSL variable on SLES
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SUSE Linux Enterprise Server 11
SUSE Linux Enterprise Server 12
They include LISTEN, ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSING, TIME-WAIT, CLOSE-WAIT, LAST-ACK, and the virtual state of CLOSED.
When a TCP connection has passed through an Active Close and is now in a TIME-WAIT state, it MUST remain in that state by TCP specification for 2*MSL.
That brings up the question,
What is the value MSL on a SLES server?
It turns out that the value is hard coded in the kernel and 2*MSL = 60 seconds.
You can find where it is hard coded here:
$(kernel_code)/include/net/tcp.h: ... #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT
* state, about 60 seconds */
... The sysctl -a | grep -i fin command at the terminal returns net.ipv4.tcp_fin_timeout = 60.
This would appear to be a way to access and alter this functionality.
But since it is hard coded in the kernel there is no way to change it at the terminal.
FIN_WAIT_1, FIN_WAIT_2, TIME_WAIT, CLOSE_WAIT, LAST_ACK
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- Document ID:7018997
- Creation Date: 16-May-2017
- Modified Date:03-Mar-2020
- SUSE Linux Enterprise Server
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