From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: To: 9fans@cse.psu.edu From: Fco.J.Ballesteros MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: [9fans] IP_DF bit and broken connections Date: Tue, 3 Dec 2002 14:09:47 +0100 Topicbox-Message-UUID: 2cdcabfe-eacb-11e9-9e20-41e7f4b1d025 Hi, we've found that if we dont disable the check for IP_DF bit while processing a fragment in ip.c, then some of our connections break from time to time. By doing this change, everything seems to work fine for us: diff /n/dump/2002/1203/sys/src/9/ip/ip.c /sys/src/9/ip/ip.c 315c315 < if(eh->frag[0] & (IP_DF>>8)){ --- > if(0 && eh->frag[0] & (IP_DF>>8)){ The reason seems to be that some times when we connect through our router, we get packet fragments which also carry the DF bit set. Since we're not network gurus, we asked to our local network programming guru and he suggested not to even look into the DF bit if we're not gatewaying. I don't think this is a `Plan 9 problem', but since it did forbid us to keep our connections alive when going through some routers, I thought it could be of help for others. We'll continue tracing this problem. In case we find out anything, we'll let you know.