Date: Sat, 12 Feb 2005 01:41:39 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: "Andrew P." <infofarmer@mail.ru> Cc: FreeBSD-Questions <freebsd-questions@freebsd.org> Subject: Re: Concealing short disconnects Message-ID: <20050212074138.GD49626@dan.emsphone.com> In-Reply-To: <420D8177.30600@mail.ru> References: <420D7EE3.5000305@mail.ru> <20050212040327.GA49626@dan.emsphone.com> <420D8177.30600@mail.ru>
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In the last episode (Feb 12), Andrew P. said: > Dan Nelson wrote: > >In the last episode (Feb 12), Andrew P. said: > >>I have a few machines behind my FreeBSD box. The box connects to > >>ISP via ppp (PPPoE protocol). It's all working very nicely, but the > >>ISP is a pain - it disconnects every 24 hours. I can reconnect in > >>just a moment - so the diconnect is usually less than a second > >>long, but many applications, like ICQ/MSN and games "feel" the > >>disconnect. The matter is that these applications can handle fairly > >>large packet loss (e.g. Counter-Strike can cope with at least > >>15-second long 100% packet loss), but AFAIK it's in the nature of > >>the TCP/UDP that a disconnect is a disconnect. > >> > >>As I know that FreeBSD is full of magic, is there any way to > >>conceal these reconnects as short moments of 100% packet loss? I am > >>ashamed to know very little about protocols' technicalities, but > >>I'll look into any sources you advise. > > > >Check to see if your IP number changes when you reconnect. If it > >does, there's nothing you really can do; the remote system you were > >talking to knew you only by your old IP, and those packets coming to > >them from this other IP are unrelated. > > It changes only once in about a week. Let's say it doesn't change > at all. What then? I'm still suspicious :) The two most common causes for connection resets are IP address changes and NAT resets. /usr/sbin/ppp keeps its NAT table across disconnects as long as the process itself stays running, so I don't think that's the cause. If you have root access to a remote system, try running tcpdump on it and your local machine while running something like top over ssh, and watch what happens when your connection drops and reconnects. -- Dan Nelson dnelson@allantgroup.com
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