From owner-freebsd-net@freebsd.org Fri Jan 20 21:12:09 2017 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 32812CB9EAA for ; Fri, 20 Jan 2017 21:12:09 +0000 (UTC) (envelope-from ermal.luci@gmail.com) Received: from mail-io0-x242.google.com (mail-io0-x242.google.com [IPv6:2607:f8b0:4001:c06::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id E9A0D1973; Fri, 20 Jan 2017 21:12:08 +0000 (UTC) (envelope-from ermal.luci@gmail.com) Received: by mail-io0-x242.google.com with SMTP id c80so9287774iod.1; Fri, 20 Jan 2017 13:12:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=rTk2npitw2vLrStAk+OGekhp7WzzCxJi6uSXkqTjWx4=; b=XJnOmU+st9tAdz/5Ng1Vka+cwR8D2uahu4Ach45hgW7k8zJvj/z4c1xIklCFqNf+9S 4RHbE8oYv3HLBXZNupIUEXPPHHxqjul6mrIYOvLXLZkNKEmy0qNdeMElYDPZlIjA7DSU ElqKSyl88haKdHydxi60lmDv2M5ncegazTeO7DEke2/lIj6JbDcoBh2zuM6oa0KvDQyx e5HpJWxpJoC7ut94wJxC7P5k6tzTcCwcKWwHHu2RlyNoc9xAViQFdaL2LpJHwqliMyUx KhPn/QW4GpEGGTDRWPpjvidAQ4uM2yZyh2P1Yntarr/t46PE5g+0JjmLIM3ASAvkzYQq h9wA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=rTk2npitw2vLrStAk+OGekhp7WzzCxJi6uSXkqTjWx4=; b=cHhpd0UEqvHOjMKPtigrl92f960bUEBnRd2jlnCBPAa0UisTep+8Gzj9rpd7QfpN+k zJ+o5nFAqIys988MKMvnwaAz2vsf+IeQcFmJhF6/36L04nkbaNzDpIUL9rCFNrmZM3Qd 1+9EEiAx6a5GpVAGUSELjx6S6NwHDtUb49a+lXIwEo0qRoL26l56YkZYrSQm26RJVy4Q MC/eNWP7/9KbMD/ed1KAmm3VF6RCzP+IMFLctFXHCZagPI3vH+wNzkvnTEN8hNbgth4K mBAldTuF/lg5sjyYGX97J488fLuVFJz6sAX8cD5AMLU77LhD6YzibQiTvxKFPd2LiHl5 24Nw== X-Gm-Message-State: AIkVDXJxEl1/J5tB3EJYkFd45FbEPhNf5PYyTHQFRgCRDCvWMQSyLIf0BPZ1sQTertODqDE7e7G1ZHhLkhPYsg== X-Received: by 10.107.171.135 with SMTP id u129mr14687661ioe.102.1484946728306; Fri, 20 Jan 2017 13:12:08 -0800 (PST) MIME-Version: 1.0 Sender: ermal.luci@gmail.com Received: by 10.107.129.99 with HTTP; Fri, 20 Jan 2017 13:12:07 -0800 (PST) In-Reply-To: <20170120205933.8948A124AEA3@mail.bitblocks.com> References: <20170120083555.ACCF9124AEA4@mail.bitblocks.com> <7C29D00C-94C0-4550-B1B2-CE307482B544@FreeBSD.org> <20170120203106.CD2C8124AEA4@mail.bitblocks.com> <20170120205933.8948A124AEA3@mail.bitblocks.com> From: =?UTF-8?Q?Ermal_Lu=C3=A7i?= Date: Fri, 20 Jan 2017 13:12:07 -0800 X-Google-Sender-Auth: 2N0aAYAKaJYjDf6hREFFvBqpFGY Message-ID: Subject: Re: pf & NAT issue To: Bakul Shah Cc: Kristof Provost , FreeBSD Net , Alan Somers Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Jan 2017 21:12:09 -0000 On Fri, Jan 20, 2017 at 12:59 PM, Bakul Shah wrote: > On Fri, 20 Jan 2017 21:43:33 +0100 "Kristof Provost" > wrote: > > On 20 Jan 2017, at 21:31, Bakul Shah wrote: > > >> 11:56:28.168693 IP 192.168.125.7.65042 > 149.20.1.200.21: Flags [P.], > > >> seq 1:10, ack 55, win 1026, options [nop,nop,TS val 198426 ecr > > >> 1468113725], length 9 > > > < 11:56:28.168712 IP 173.228.5.8.52015 > 149.20.1.200.21: Flags [P.], > > > seq 3080825147:3080825156, ack 3912707414, win 1026, options > > > [nop,nop,TS val 198426 ecr 1468113725], length 9 > > > > > > Right here we see the problem. NAT mapping for the > > > port changed from 63716 to 52015. > > > > > Changing source ports is an entirely normal NAT behaviour. > > > > The best explanation is this: imagine that you have two clients A and B, > > both connect to X on port 80 via the NAT gateway G. > > Both use port 1000 as their source port. > > A connects, and the gateway maps A:1000 -> X:80 to G:1000 -> X:80. > > B connects, and now the gateway has to map B:1000 -> X:80 onto G:1000 -> > > X:80, but then it wouldn't be able to tell the two connections apart. > > That't can remap it onto G:1001 -> X:80 instead. > > It is the same connection! As a tcp connection is identified > by , If the port number > changes on the same connection, the remote side would see this > as a separate connection. > Most probably your timeouts are aggressive on states garbage collection. Give a look to those state limit teardown it might improve things. > _______________________________________________ > freebsd-net@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > > -- > Ermal >