Monitoring of Internet connection

[G.O.]

On 6/6/07, Ben Scott <dragonhawk at gmail.com> wrote:
> Hi all,
>
>   I'm looking to monitor the reliability of our Internet connection at
> $DAYJOB, from the inside out.  I'm familiar (in concept at least) with
> monitoring a bunch of hosts and services with a tool like Nagios, but
> here I'm only looking to monitor one link, and closely.
>
>   I could just run ping in a screen(1) session, of course.  Indeed,
> that's what I'm often doing now.  But I'm thinking a more
> sophisticated approach is possible, and could yield more informative
> results.
>
>   In practical terms, I'm thinking about some kind of reverse
> exponential back-off.  When things appear to be working, sending
> occasional probes is fine.  But when a probe indicates trouble, follow
> up immediately with more.  If it looks like things are working, slowly
> back off.  If things remain not-working, then keep hammering at it
> until they start working.
>
>   I'm also wondering about tracking performance (% loss and RTT) vs
> packet size and/or padding patterns.
>
>   Reason why I'm asking all this is that our feed at work has recently
> (past couple of days) developed some weird trouble.  It's intermittent
> but persistent.  The provider has been very responsive in
> acknowledging it and is trying to figure WTF is going on, but they're
> lacking in immediate answers, and I'm trying to gather more
> information, to help them as much as us.
>
>   Can anyone here comment on this?
>
     Hi,
     They used nload for this (or similar) purposes at my former
employer. You might want to check it out:
         http://sourceforge.net/projects/nload/

    Hope this helps.
   Gurhan

>   (Aside: Fellow IT geeks may be interested in the failure mode.  My
> local gateway (Linux box) is not getting an ARP reply for the peer
> gateway.  With a sniffer, I see our gateway sending ARP queries, but
> never an ARP response from the peer.  But I see the peer's ARP and our
> response.  I also see TCP/UDP packets coming in, so the peer has our
> MAC.  (Our box never replies, since it can't ARP.)  The provider says
> they can see our CPE in their management system.  The trouble comes
> and goes, with no pattern I've been able to discern.  Oh, and while
> this happens, the ping test I'm running will occasionally report a
> burst of packets with RTT's of 300+ seconds.  Not milliseconds,
> *seconds*.  I don't know how TTL is even allowing that.  This is one
> of those hair-reducing problems.)
>
> -- Ben
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