[outages] XO in DC/Herndon: Can only ping even numbered IPs?

[William R. Lorenz]

Hi Cary,

On Mon, 13 Jun 2011, Cary Wiedemann wrote:

> Greetings list,
>
> We have a few customers in the Fairfax County/Washington DC area with
> XO-provided T1 circuits that can only access hosts with an EVEN
> numbered last octet in their IP address.
>
> For example I personally host a server in Equinix Ashburn (with
> Carpathia) on a /28 and the XO T1's can only ping the EVEN numbered
> IPs, for example:
> 209.222.152.120 - can ping/http/etc
> 209.222.152.121 - no access
> 209.222.152.122 - can ping/http/etc
> 209.222.152.123 - no access
>
> The is doubly-confirmed via traceroute as only even numbered routers'
> responses make it back.

XO recently implemented automatic abuse-related filtering at their edge
routers.  You may want to check to make sure these individual IPs aren't
triggering one of the automatic filtering rules that null routes the /32s.

Hope this helps,

--
William R. Lorenz