Date: Thu, 24 Nov 2011 11:07:08 +0100 From: Kees Jan Koster <kjkoster@gmail.com> To: freebsd-questions@freebsd.org Subject: Re: Diagnosing packet loss Message-ID: <97326E87-B3A2-460F-AE9D-259710B36EA2@gmail.com> In-Reply-To: <4ECC2CD0.8040902@sentex.net> References: <B0BE38BD-CE86-4D42-9215-933150BA07D9@gmail.com> <4ECC2CD0.8040902@sentex.net>
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Dear All, Thank you so much for the excellent suggestions. I can tell some of you = have a lot of experience troubleshooting this issue. At this stage I ruled out hardware or network issues. These are server = grade network interfaces, new cables and the ifconfig configuration = seems in order. netstat shows no collisions or packet errors for the = past week or so. I am dead certain there is no dupe IP. The other machines on the switch = are currently off (test and load test box) and I still see packet loss. = There simply is no other machine on the subnet that might have the same = IP. This seems to be local to my machine. Here is another reason why I say = that: I can reliably transmit data when I bind to the aliased IP = address: If I use mtr to measure packet loss from saffron (the stricken = machine) to cumin (another machine in a different data center) I see the = following: saffron (ip address a) -> cumin: packet loss saffron (ip address b) -> cumin: no packet loss cumin -> saffron (ip address a): packet loss cumin -> saffron (ip address b): no packet loss This is consistent from running mtr for 5 minutes straight. This to me = shows that the hardware is fine. Using the alias IP address I can run = with no packet loss for as long as I like. Sooo.... Now what? I am completely at a loss. :-/ -- Kees Jan http://java-monitor.com/ kjkoster@kjkoster.org +31651838192 I hate unit tests; I much prefer the illusion that there are no errors = in my code. -- = Hendrik Muller
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