Internet Connectivity Monitoring

[Alex Dehaini]

Hmmm,

I would say your upstream providers should allow your nagios server
(router) icmp access without applying their DDoS ACLs but again, it's
difficult to get other people to work with you when you don't control
the resources.

Alex

On 1/25/08, Giles Coochey <gcoochey at sapphire.gi> wrote:
> Hi Alex,
>
>
>
> Unfortunately most of our upstreams implement CPP (Control Plane
> Policing) to prevent DDoS attacks, which essentially means that given a
> certain threshold of ICMP messages the routers begin to drop those
> packets purposefully to avoid flooding the routers control plane. I do
> monitor those, but have notifications turned off because of the false
> positives.
>
>
>
> The other problem is that one of the scenarios I see once in a while is
> one of our upstreams may withdraw all their BGP routes and while BGP
> converges we may see momentary loss to certain sites. We use BGP
> communities to define which provider we use for different geographic
> locations, so having geographic monitors is quite important for us
> (unfortunately, not important enough to host our own servers in those
> geographic locations, nor to use a performance monitoring service such
> as Keynote for the same).
>
>
>
> Even worse, thankfully only happened just once, one of our upstreams
> encountered an issue where they lost connectivity, but didn't withdraw
> their BGP routes from our tables. (Ouch!).
>
>
>
> Cheers,
>
>
>
> Giles
>
>
>
> ________________________________
>
> From: Alex Dehaini [mailto:alexdehaini at gmail.com]
> Sent: 25 January 2008 11:12
> To: Giles Coochey; nagios-users at lists.sourceforge.net
> Subject: Re: [Nagios-users] Internet Connectivity Monitoring
>
>
>
> We monitor our upstream provider core routers. Basically, we monitor
> every physical device between us and them. So, if any device goes down,
> we can tell where the problem is originating from.
>
>
>
> Secondly, if you have a co-located server outside your network, you can
> monitor that as well.
>
>
>
> Alex
>
> On Jan 25, 2008 8:54 AM, Giles Coochey < gcoochey at sapphire.gi> wrote:
>
> Hi List,
>
> As part of our Internet Connectivity monitoring I monitor a set of
> websites on the Internet from a diverse number of locations
> geographically.
>
> There are some issues with this:
>
> (a) I have to avoid sites that use Content Delivery Systems such as
> Akamai, because as we host such boxes ourselves the websites actually
> load from local servers which we host rather than the intended
> geographic location. Most large sites such as www.yahoo.com and
> www.google.com use these content delivery systems.
> (b) I have to avoid small sites which often go down due to lack of
> redundancy in their implementation.
> (c) I have to avoid sites which might get pretty annoyed that I'm
> pulling their homepage once every 10-15 minutes just to see if I'm
> getting good access.
>
> I would like to hear from others on the list as to what they do to check
> Internet Connectivity and whether they do any smart stuff to include
> multiple connectivity checks as a single service check.
>
> What do you do?
>
> Thanks
>
> Giles
>
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>
> --
> Alex Dehaini
> Developer
> Site - www.alexdehaini.com
> Email - alexdehaini at gmail.com
>
>


-- 
Alex Dehaini
Developer
Site - www.alexdehaini.com
Email - alexdehaini at gmail.com

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