[Bug 256217] [tcp] High system load because of interrupts with RACK

From: <bugzilla-noreply_at_freebsd.org>
Date: Sat, 29 May 2021 13:09:37 +0000
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256217

--- Comment #11 from Christos Chatzaras <chris_at_cretaforce.gr> ---
SSHGuard ( https://www.freshports.org/security/sshguard ) is a tool that checks
/var/log/auth.log , /var/log/maillog, etc and blocks IPs that try to brute
force passwords. When someone tries to login for example to SSH multiple times
using wrong password it blocks their IP using IPFW (or PF). As the remote host
is not "reachable" any more we can't receive any packets from it which I
believe makes the connection to stuck in LAST_ACK state.

I tried to use a CURRENT kernel with 13.0 userland, I connect successfully
using SSH, but after I run the "wrk benchmark" the server hang. Maybe I have to
build a CURRENT userland too. I ask datacenter to connect a KVM to see if
monitor shows more information.

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Received on Sat May 29 2021 - 13:09:37 UTC

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