linux-kernel - Re: [bug report, linux 6.15-rc4] A large number of connections in the SYN_SENT state caused the nf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAN2Y7hzKd+VxWy56q9ad8xwCcHPy5qoEaswZapnF87YkyYMcsA@mail.gmail.com>
Date: Wed, 28 May 2025 21:26:22 +0800
From: ying chen <yc1082463@...il.com>
To: Florian Westphal <fw@...len.de>
Cc: pablo@...filter.org, kadlec@...filter.org, davem@...emloft.net, 
	edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com, 
	netfilter-devel@...r.kernel.org, coreteam@...filter.org, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [bug report, linux 6.15-rc4] A large number of connections in the
 SYN_SENT state caused the nf_conntrack table to be full.

On Wed, May 28, 2025 at 9:10 PM Florian Westphal <fw@...len.de> wrote:
>
> ying chen <yc1082463@...il.com> wrote:
> > Hello all,
> >
> > I encountered an "nf_conntrack: table full" warning on Linux 6.15-rc4.
> > Running cat /proc/net/nf_conntrack showed a large number of
> > connections in the SYN_SENT state.
> > As is well known, if we attempt to connect to a non-existent port, the
> > system will respond with an RST and then delete the conntrack entry.
> > However, when we frequently connect to non-existent ports, the
> > conntrack entries are not deleted, eventually causing the nf_conntrack
> > table to fill up.
>
> Yes, what do you expect to happen?
I understand that the conntrack entry should be deleted immediately
after receiving the RST reply.