From: Gert Doering Date: Sun, 2 Dec 2012 22:11:11 +0100 Message-Id: <1354482672-16136-1-git-send-email-gert@...1296...> Subject: [Openvpn-devel] Implement --mssfix handling for IPv6 packets List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: openvpn-devel@lists.sourceforge.net Hi, in the next mail you'll find a patch to extend the existing --mssfix code to handle IPv6 packets as well. The actual mssfix implementation is only about half the change, but I took the liberty to rename process_ipv4_header() to process_ip_header(), and (after discussion on IRC) the PIPV4_MSSFIX flag to PIP_MSSFIX - to make it obvious that this is no longer "IPv4 only". The code has been tested on our corporate VPN server for 3 days now, and did what advertised - adjusted MSS; not breaking anything else. It does fix the connectivity problems one of my users had - sitting behind a router with broken PMTU handling *and* broken IPv4 fragment handling, which killed IPv6 SSH-Sessions (all crypted, not compressible) quite reliably. Testing this is a bit tricky - the t_client framework won't cover it (as it doesn't do TCP payload tests yet), so to actually *see* the change you either need to have a broken network wrt IPv4 PMTU/fragment handling before, or look at TCP SYN / SYN ACK packets with wireshark. Anyway, I believe it's ready for inclusion in RC2, and should most definitely be in 2.3-RELEASE (as we'll see more users with broken networks then). gert