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

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Message-ID: <aDcLIh2lPkAWOVCI@strlen.de>
Date: Wed, 28 May 2025 15:09:54 +0200
From: Florian Westphal <fw@...len.de>
To: ying chen <yc1082463@...il.com>
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.

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?