[CentOS] 6.5 vpn/gre/ospf breakage

[SilverTip257]

On Thu, Mar 27, 2014 at 8:24 AM, Steve Clark <sclark at netwolves.com> wrote:

> Hi List,
>
>
Hi Steve,


> FYI.
>
> We have been using CentOS 6.4 and have 2 vpn/gre tunnels to separate cisco
> rtrs using ospf.
> with kernel 2.6.32-358.23.2
>
> We have upgraded to 6.5 bit using kernel 2.6.32-431.5.1 and the exact same
> configuration scripts for
> our vpn/gre tunnels.
>

There was a brief thread (total of three posts) on multicast changes with
the newer CentOS 6 kernel.
http://lists.centos.org/pipermail/centos/2014-February/141062.html

Apparently something odd going on in 2.6.32-431.x.x -- functionality that
operates fine in the older 2.6.32-358.x.x kernels.


>
> What I see is the first gre tunnel works great and I get an ospf neighbor.
>
> The second tunnel comes up and I can ping across it and I see our side
> sending hello packets in the gre tunnel
> but I never receive any hello packets from the cisco.
>
> The cisco sees our hellos because it goes into the Init state. I do a
> tcpdump
> and I see esp traffic coming from the cisco like it is sending hellos but
> they never show up in a tcpdump
> on the gre tunnel. It is like the kernel is not delivering them.
>
> Also my gre tunnels on CentOS 6.5 are named gre1 at NONE and gre2 at NONE with
> an ip a s, while on the 6.4 CentOS system
> they show up as only gre1 and gre2?  Whats with the @NONE?
>
> Looking at the Changelog of the kernel a lot of changes to the ip_gre
> module were made in 2.6.32-380
>
>
Sounds like you might be aware of the post I linked to above.
( In case you're not, I'll send this message anyways. )


>
> --
> Stephen Clark
> *NetWolves Managed Services, LLC.*
> Director of Technology
> Phone: 813-579-3200
> Fax: 813-882-0209
> Email: steve.clark at netwolves.com
> http://www.netwolves.com
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> http://lists.centos.org/mailman/listinfo/centos
>



-- 
---~~.~~---
Mike
//  SilverTip257  //