From: Hannes Frederic Sowa <hannes@stressinduktion•org>
To: Stas Sergeev <stsp@list•ru>
Cc: netdev <netdev@vger•kernel.org>
Subject: Re: Q: bad routing table cache entries
Date: Tue, 12 Jan 2016 17:10:59 +0100 [thread overview]
Message-ID: <56952593.8040409@stressinduktion.org> (raw)
In-Reply-To: <569523C0.5040504@list.ru>
On 12.01.2016 17:03, Stas Sergeev wrote:
> 12.01.2016 18:52, Hannes Frederic Sowa пишет:
>> On 12.01.2016 16:34, Hannes Frederic Sowa wrote:
>>> On 29.12.2015 11:54, Stas Sergeev wrote:
>>>> Hello.
>>>>
>>>> I was hitting a strange problem when some internet hosts
>>>> suddenly stops responding until I reboot. ping to these
>>>> host gives "Destination Host Unreachable". After the
>>>> initial confusion, I've finally got to
>>>> ip route get
>>>> and got something quite strange.
>>>>
>>>>
>>>> Example for GOOD address (the one that I can ping):
>>>>
>>>> ip route get 91.189.89.237
>>>> 91.189.89.237 via 192.168.8.1 dev eth0 src 192.168.10.202
>>>> cache
>>>>
>>>>
>>>> Example for BAD address (the one that stopped responding):
>>>>
>>>> ip route get 91.189.89.238
>>>> 91.189.89.238 via 192.168.0.1 dev eth0 src 192.168.10.202
>>>> cache <redirected>
>>>
>>> I tried to understand this thread and now wonder why this redirect route
>>> isn't there always. Can you please summarize again why this shouldn't
>>> happen? It looks totally fine to me from the configuration of your
>>> router and the subnet masks.
>>
>> Just an addendum:
>>
>> In IPv6 a redirect is seen as a notification telling hosts, this new address is on the same link as you. I think this semantic is the same for IPv4, so we are informing you that in essence you are
>> getting a /32 route installed to your new interface and can do link layer resolving of the new host.
>>
>> I do think this is valid and fine.
> You can't call "valid and fine" something that doesn't
> work, at first place. Why and where does it fail, was the
> subject of this thread.
In terms of the shared media specification
<https://tools.ietf.org/html/rfc1620> it is valid and fine.
You can also disable shared_media on the client and it won't accept such
redirects anymore. It is just what we defined as the default.
> If you think router did the right thing, then please explain
> the breakage from that point of view.
Hope it makes sense.
Bye,
Hannes
next prev parent reply other threads:[~2016-01-12 16:11 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-29 10:54 Q: bad routing table cache entries Stas Sergeev
2015-12-29 11:58 ` Sowmini Varadhan
2015-12-29 12:06 ` Stas Sergeev
2015-12-29 12:32 ` Sowmini Varadhan
2015-12-29 12:43 ` Stas Sergeev
2015-12-29 13:19 ` Stas Sergeev
2015-12-29 15:22 ` Sowmini Varadhan
2015-12-29 15:38 ` Stas Sergeev
2015-12-29 17:40 ` Stas Sergeev
2015-12-30 12:42 ` Stas Sergeev
2015-12-30 14:17 ` Eric Dumazet
2015-12-30 17:56 ` David Miller
2016-01-04 1:05 ` Sowmini Varadhan
2016-01-04 1:32 ` Stas Sergeev
2016-01-04 17:23 ` Stas Sergeev
2016-01-12 14:40 ` Stas Sergeev
2016-01-12 14:47 ` Sowmini Varadhan
2016-01-12 20:33 ` David Miller
2016-01-12 15:34 ` Hannes Frederic Sowa
2016-01-12 15:52 ` Hannes Frederic Sowa
2016-01-12 16:03 ` Stas Sergeev
2016-01-12 16:10 ` Hannes Frederic Sowa [this message]
2016-01-12 16:42 ` Stas Sergeev
2016-01-12 16:56 ` Stas Sergeev
2016-01-12 17:06 ` Hannes Frederic Sowa
2016-01-12 17:18 ` Stas Sergeev
2016-01-12 17:26 ` Hannes Frederic Sowa
2016-01-12 17:33 ` Stas Sergeev
2016-01-12 17:47 ` Hannes Frederic Sowa
2016-01-12 20:43 ` Stas Sergeev
2016-01-12 22:26 ` Hannes Frederic Sowa
2016-01-12 22:57 ` Stas Sergeev
2016-01-12 23:07 ` Hannes Frederic Sowa
2016-01-13 12:59 ` Stas Sergeev
2016-01-12 17:41 ` Stas Sergeev
2016-01-12 15:57 ` Stas Sergeev
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