Development issues regarding the cerowrt test router project
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From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Dave Taht <dave.taht@gmail.com>
Cc: bloat <bloat@lists.bufferbloat.net>,
	 cerowrt-devel <cerowrt-devel@lists.bufferbloat.net>
Subject: Re: [Cerowrt-devel] [Bloat] talking at linux plumbers in portugal next week
Date: Tue, 3 Sep 2019 14:23:56 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1909031420320.21548@uplift.swm.pp.se> (raw)
In-Reply-To: <CAA93jw5OS9zxQasFFn6C2354yvyFO0xin+O6jYFrx46Ax5Tx=g@mail.gmail.com>

On Mon, 2 Sep 2019, Dave Taht wrote:

> with copy-pasted parameters set in the 90s - openwrt's default, last I
> looked, was 25/sec.

-A syn_flood -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -m limit --limit 25/sec --limit-burst 50 -m comment --comment "!fw3" -j RETURN
-A syn_flood -m comment --comment "!fw3" -j DROP

Well, it's got a burst-size of 50. I agree that this is quite 
conservative.

However, at least in my home we're not seeing drops:

# iptables -nvL | grep -A 4 "Chain syn_flood"
Chain syn_flood (1 references)
  pkts bytes target     prot opt in     out     source               destination
  2296  113K RETURN     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp flags:0x17/0x02 limit: avg 25/sec burst 50 /* !fw3 */
     0     0 DROP       all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* !fw3 */

But you might be right that in places with a lot more clients then this 
might indeed cause problems.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se

  reply	other threads:[~2019-09-03 12:23 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-03  0:47 [Cerowrt-devel] " Dave Taht
2019-09-03 12:23 ` Mikael Abrahamsson [this message]
2019-09-03 14:21   ` [Cerowrt-devel] [Bloat] " Dave Taht
2019-09-03 14:35     ` [Cerowrt-devel] Revising the synflood limit Dave Taht
2019-09-10 18:08       ` Maciej Sołtysiak
2019-09-10 22:35         ` Dave Taht
2019-09-23  9:37           ` Maciej Sołtysiak
2019-09-03 14:45     ` [Cerowrt-devel] [Bloat] talking at linux plumbers in portugal next week Toke Høiland-Jørgensen
2019-09-03 14:47       ` Dave Taht
2019-09-03 15:10         ` Toke Høiland-Jørgensen
2019-09-03 15:21           ` Dave Taht
2019-09-03 15:22     ` Sebastian Moeller

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