From: Stas Sergeev <stsp@list•ru>
To: Sowmini Varadhan <sowmini.varadhan@oracle•com>
Cc: netdev <netdev@vger•kernel.org>
Subject: Re: Q: bad routing table cache entries
Date: Tue, 29 Dec 2015 15:06:49 +0300 [thread overview]
Message-ID: <56827759.8020605@list.ru> (raw)
In-Reply-To: <20151229115821.GA9352@oracle.com>
29.12.2015 14:58, Sowmini Varadhan пишет:
> On (12/29/15 13:54), Stas Sergeev wrote:
>>
>> 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>
> :
>> Now, 192.168.0.1 is also a valid gateway, but it is outside
>> of the network mask for the eth0 interface:
> :
>> So my question is: why does linux allow an invalid redirect
>> entries? Is it a problem with my setup, or some kernel bug,
>> or some router setup problem? Where should I look into, to
>> nail this down?
>
> Seems like the problem is in the router that is sending
> the bad redirect. You would have to check into the configuration
> and/or implementation of the router- it should not be sending
> back a redirect in the above case (different netmasks) even
> if the ingress and egress physical interfaces are the same.
Router on 192.168.8.1 is just a PC with ubuntu, w/o any special
software. I'd be very surprised if it does so. As I understand,
linux would accept such ICMP redirect only from the router, or
could someone else also send them?
But what worries me more, is the question:
Should the linux kernel really silently accept those, breaking
the routing in a completely unexpected ways? Isn't it a bug?
The sanity check against netmask looks trivial, so why it is not there?
next prev parent reply other threads:[~2015-12-29 12:06 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 [this message]
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
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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