TCP SYN packets intermittently go unanswered
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net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 0 net.ipv4.tcp_tw_recycle = 0
hostname:~ # sysctl -w net.ipv4.tcp_tw_recycle = 0 hostname:~ # sysctl -w net.ipv4.tcp_tw_reuse = 0
hostname:~ # cd /proc/sys/net/ipv4 hostname:/proc/sys/net/ipv4 # echo 0 > tcp_tw_recycle hostname:/proc/sys/net/ipv4 # echo 0 > tcp_tw_reuseKeep in mind though, that this change will not survive a reboot !
tcp_tw_recycle (Boolean; default: disabled; Linux 2.4 to 4.11) Enable fast recycling of TIME_WAIT sockets. Enabling this option is not recommended as the remote IP may not use monotonically increasing timestamps (devices behind NAT, devices with per-connection timestamp offsets). See RFC 1323 (PAWS) and RFC 6191. tcp_tw_reuse (Boolean; default: disabled; since Linux 2.4.19/2.6) Allow to reuse TIME_WAIT sockets for new connections when it is safe from protocol viewpoint. It should not be changed without advice/request of technical experts.
- The tcp_tw_recycle was removed from the kernel upstream:
- tcp_tw_reuse allows the reuse of a client port immediately after the connection has been closed, even though the connection is still in TIME_WAIT state. A precondition for it to take effect is that TCP timestamps are enabled, i.e. net.ipv4.tcp_timestamps = 1, which is the default on most modern systems.
SAP supports the use of net.ipv4.tcp_tw_reuse = 1 parameter as referenced in SAP Note 2382421 *only* under the conditions listed there.
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- Document ID:7023254
- Creation Date: 08-Aug-2018
- Modified Date:05-Nov-2020
- SUSE Linux Enterprise Server
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