CARP and routing

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CARP and routing

Toni Mueller-10
Hi,

I discover that CARP and routing don't always mix well:

  Internet --- host1  ---- host2

If host1 and host2 have a CARP interface with the same IP, then packets
destined for that IP don't ever reach host2, even if the interface on
host1 is in BACKUP state.



Kind regards,
--Toni++

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Re: CARP and routing

michal-49
On 25/11/10 12:22, Toni Mueller wrote:

> Hi,
>
> I discover that CARP and routing don't always mix well:
>
>    Internet --- host1  ---- host2
>
> If host1 and host2 have a CARP interface with the same IP, then packets
> destined for that IP don't ever reach host2, even if the interface on
> host1 is in BACKUP state.
>
>
>
> Kind regards,
> --Toni++
>
Wait, do you mean;


                    -------- Host1
Internet --- |
                    -------- Host 2

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Re: CARP and routing

Robert Hoffmann-2
In reply to this post by Toni Mueller-10
On Thu, 25 Nov 2010 13:22:13 +0100
Toni Mueller <[hidden email]> wrote:
>   Internet --- host1  ---- host2

Because your setup should rather look like this?

Internet --- switch --- host1 --- switch --- LAN
                  + --- host2 ----+

regards,
Robert

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Re: CARP and routing

Toni Mueller-10
In reply to this post by michal-49
On Thu, 25.11.2010 at 13:15:06 +0000, Michal <[hidden email]> wrote:

> On 25/11/10 12:22, Toni Mueller wrote:
> >I discover that CARP and routing don't always mix well:
> >
> >   Internet --- host1  ---- host2
> Wait, do you mean;
>
>
>                    -------- Host1
> Internet --- |
>                    -------- Host 2

No, I mean Internet --- host1 --- host2.

I'm just digging the code to find the place where the kernel decides
that a given IP is his, and would appreciate pointers.


Kind regards,
--Toni++

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Re: CARP and routing

michal-49
In reply to this post by Robert Hoffmann-2
On 25/11/10 13:20, Robert Hoffmann wrote:

> On Thu, 25 Nov 2010 13:22:13 +0100
> Toni Mueller<[hidden email]>  wrote:
>>    Internet --- host1  ---- host2
> Because your setup should rather look like this?
>
> Internet --- switch --- host1 --- switch --- LAN
>                    + --- host2 ----+
>
> regards,
> Robert
>
This is what I was trying to get at...the way you draw your diagram, I
can't understand what your trying to do with carp if you have

internet -- host1 -- host2

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Re: CARP and routing

Toni Mueller-10
On Thu, 25.11.2010 at 14:29:39 +0000, Michal <[hidden email]> wrote:
> >Because your setup should rather look like this?
> >
> >Internet --- switch --- host1 --- switch --- LAN
> >                   + --- host2 ----+
> This is what I was trying to get at...the way you draw your diagram,
> I can't understand what your trying to do with carp if you have
>
> internet -- host1 -- host2

I have a low-resources application running on host2 which I'd like to
be available at all times, but would prefer to not have it on host1 in
general.


I also have

> >Internet --- switch --- host1 --- switch --- LAN
> >                  + --- host3 ----+

but this is not very relevant in this context. Ok, a better picture
would be


Internet --- switch --- host1 --- switch --- host2
                  + --- host3 ----+



Kind regards,
--Toni++