From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x531.google.com (mail-ed1-x531.google.com [IPv6:2a00:1450:4864:20::531]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id CC8EB3B2A4 for ; Tue, 22 Dec 2020 16:45:56 -0500 (EST) Received: by mail-ed1-x531.google.com with SMTP id cw27so14328755edb.5 for ; Tue, 22 Dec 2020 13:45:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:cc:references:from:subject:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=+Gqe3N91gWni1XtzFrCFYcymGLKAEx9tQ8FjrWncZNc=; b=H0kUEpRU7oVsP2WDFHNp32Yb0yEnuLv4SiTKlgdlNZGFrZHfw25ECMcVcwnpjCO/a0 LjqN9zg81hjexYEm/K8ZRor6kBdhnn1tpfJGitCoN+fOUDO50Md7E2ik9NA4AK1hjkvw xh3rGJxsctXb+IpnrCDwgnzWlPSqSQeLyN+YtYfAFvWZoiJYC3GE0eDsKguZUCk0+Z6D 9jwMIeq4eKNsLHg3MLiIacgyvToEHyD2TeH8T5bcug1vDCZ20cCmzLjIv5RV9upg/0P4 je49kmWvBEU07z3LUSz+1BYBSBPqzpXBgTVviKpxEJasIaCrlxDI5rLiPyQ2l3cZQemv CDNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=+Gqe3N91gWni1XtzFrCFYcymGLKAEx9tQ8FjrWncZNc=; b=XuSmZCmsXic2LxRXoIlGH5lT1h/AQXlRs3VH1r7kCvKijeAsKjeCi2jdI7++ATs+lh +sT9yq3DySLTarovKt1C0NPndTvTPCbX1fD0FKtseD+IJIqAzoVaFf5wSRkngRrO8R/2 BCwPK7eexWCw23uO9vzfMIWdQilZa+xb8Eff2j4A1wD5ejxSvm/4u0YkQkfJLS7/pFQ/ IXJe6QmQzJsB1EQUHz30uTFDxheRM0jtiRvkoRj7MtFHJTHjKbt5TUT5hUxBuNACwflj dAcyHSkrNZdDCKEWh3AwOclMwUdqy9xQwlqVmHRRhb4nUXSV7iQZpAvb6hyTmFu0J16N /+7Q== X-Gm-Message-State: AOAM531JPvbIn20sxtU3Y5NZ5NNAvr0XRFAhbCfZSihmd8XU5DQuAHzV YO2aVAmIBg4gvzoIPdaqUVGZn8+FFZY= X-Google-Smtp-Source: ABdhPJx3Z8Fv4OaWktK7IuWFrmfNw1ZdlyEF5gfdTT5SjyrNTjzogrL5TDuL0p5po23P1bTzcubwug== X-Received: by 2002:a05:6402:8d5:: with SMTP id d21mr12074257edz.57.1608673555765; Tue, 22 Dec 2020 13:45:55 -0800 (PST) Received: from [192.168.1.116] (cpe90-146-174-71.liwest.at. [90.146.174.71]) by smtp.gmail.com with ESMTPSA id qp16sm10840822ejb.74.2020.12.22.13.45.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Dec 2020 13:45:55 -0800 (PST) To: Jonathan Morton Cc: cake@lists.bufferbloat.net References: <421ffd89-0c2c-1187-380c-03a0968f4095@gmail.com> From: xnor Message-ID: <8c4e1bbf-7e3f-388a-ee60-e1d517029a9c@gmail.com> Date: Tue, 22 Dec 2020 22:44:43 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] ECN not working? X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Dec 2020 21:45:57 -0000 > Not all servers have ECN support enabled. A SYN-ACK without the ECE bi= t 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 outboun= d). > > - Jonathan Morton Why would my server not support ECN? I have full control over both the=20 client and server, my previous mail contained the ECN kernel parameter=20 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=20 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=20 conntrack, which on the server is disabled for some ports, though I=20 couldn't find any mention of this anywhere.