From owner-freebsd-net@freebsd.org Thu Oct 25 01:39:18 2018 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6D08810779F3 for ; Thu, 25 Oct 2018 01:39:18 +0000 (UTC) (envelope-from hegui_you@126.com) Received: from n6.nabble.com (n6.nabble.com [162.255.23.37]) by mx1.freebsd.org (Postfix) with ESMTP id 144F984062 for ; Thu, 25 Oct 2018 01:39:18 +0000 (UTC) (envelope-from hegui_you@126.com) Received: from n6.nabble.com (localhost [127.0.0.1]) by n6.nabble.com (Postfix) with ESMTP id 65F9CA2C1057 for ; Wed, 24 Oct 2018 18:39:17 -0700 (MST) Date: Wed, 24 Oct 2018 18:39:17 -0700 (MST) From: star To: freebsd-net@freebsd.org Message-ID: <1540431557414-0.post@n6.nabble.com> Subject: IP_BINDANY(SYN_SENT ): return packets not accepted by kernel MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Oct 2018 01:39:18 -0000 Hello all, I am testing IP_BINDANY functionality with a small C program. I can bind to a foreign (non existing) address, and syn packets are being sent with the bound source IP address and port. Return (ACK) packets are reaching the host (I can see the SYN-ACK packet in tcpdump), but the third packet in TCP handshake is not getting generated. It looks like the second SYN-ACK is not getting accepted by the kernel. My ipfw: root@bsd:~ # ipfw list 00100 fwd 127.0.0.1,3128 tcp from any to any 80 in recv igb1 00300 fwd 127.0.0.1 ip from any to any uid 0 in recv igb0 65534 allow ip from any to any 65535 deny ip from any to any Refer to other pages: http://freebsd.1045724.x6.nabble.com/IP-BINDANY-return-packets-not-accepted-by-kernel-td4017905.html but not work! can anybody help me? Thanks -- Sent from: http://freebsd.1045724.x6.nabble.com/freebsd-net-f4005075.html