[outages] Cogent/Level3 peering issue?

[Jonathan Lassoff]

On Sat, Nov 17, 2012 at 11:19 PM, Agle, Jeff
<jeff.agle at financialpartners.com> wrote:
> I’m seeing a lot of high latency and packet loss from my Cogent Co. link in
> MA towards IP 4.2.2.2.  Not present on other local ISP.  Traces would seem
> to indicate the problem is at Cogent’s POP to L3.  Can anyone confirm, or
> sympathize?

As discussed many times on here in the past, 4.2.2.2 is a bad
(statistically) place to point measurements at. While publicly
addressable and pingable, it's sometimes rate-limited.

FWIW, I can connect and query the San Jose anycast site just fine.

If you're interested in the 4.2.2.2 / 4.2.2.1 resolvers, by all means
ping and measure them based on DNS response time.
However, if you're just looking for an indication of routing-path
health, try measuring other destinations that take similar paths and
summarize those points to factor out the behavior of 4.2.2.0/29 hosts.

Cheers,
jof