nanog mailing list archives

Re: Pinging routers for network status


From: "John M . Brown" <jmbrown () ihighway net>
Date: Mon, 18 Dec 2000 01:36:52 -0700


Customers are constantly pinging our edge router, ns, or mail server.
Recently we had a flood of "your network is down" calls because customers
where pinging a well known site we host.  That site decided to block
all ICMP (don't start with me). We have since tweeked there filters to 
allow certain ICMP things thru.

End users (read those that write the checks) seem to put a lot of
stock into the ping and trace route values.  Certainly the DSL
customers do.

Yet, I am seeing the "net" becoming more asymetric, and those ICMP
ECHO / ECHO-REPLY packets aren't taking nearly the same path
as they used to.

jmbrown

On Mon, Dec 18, 2000 at 12:12:15AM -0800, Bill Woodcock wrote:

      On 17 Dec 2000, Sean Donelan wrote:
    > Most network providers ping their routers for network status.  Several
    > providers even track RTT to detect changes.  But very few customers
    > connect to routers. 

I'd disagree with this, at least from what I've observed of our
customers...  I see a fairly steady stream of ICMP directed to the
loopback and tail-circuit interfaces of our core and tail-circuit routers
from customer address space, and if I were to guess, I'd say that 10%-15%
of our customers were using some sort of ICMP-based uptime-monitoring
packages which are looking at their Internet connection, among other
things.  From talking with them, I think most of them are using them to
monitor WAN and VPN link uptime, and that they just throw our router into
the list as an afterthought.

                                -Bill






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