From: xnor <xnoreq@gmail.com>
To: Jonathan Morton <chromatix99@gmail.com>
Cc: cake@lists.bufferbloat.net
Subject: Re: [Cake] ECN not working?
Date: Tue, 22 Dec 2020 22:44:43 +0100 [thread overview]
Message-ID: <8c4e1bbf-7e3f-388a-ee60-e1d517029a9c@gmail.com> (raw)
In-Reply-To: <DDC33147-4B1D-45A0-B73B-0641A4050A68@gmail.com>
> Not all servers have ECN support enabled. A SYN-ACK without the ECE bit set indicates it does not. The connection then proceeds as Not-ECT.
>
> I'm reasonably sure Akamai has specifically enabled ECN support. A lot of smaller webservers are probably running with the default passive-mode ECN support as well (ie. will negotiate inbound but not initiate outbound).
>
> - Jonathan Morton
Why would my server not support ECN? I have full control over both the
client and server, my previous mail contained the ECN kernel parameter
configuration, and I also did the packet capture directly on the server.
The server is using fq_codel with ecn enabled, and also has a basic
nftables firewall but it doesn't mess with packet headers or do anything
fancy.
The only thing I can think of could be a hidden requirement on
conntrack, which on the server is disabled for some ports, though I
couldn't find any mention of this anywhere.
prev parent reply other threads:[~2020-12-22 21:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 20:06 xnor
2020-12-22 20:15 ` Jonathan Morton
2020-12-22 21:44 ` xnor [this message]
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