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

[Cary Wiedemann]

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.

Getting very slow/doubtful responses from XO support so I'm just
reaching out to this list to see if anyone else is affected.

I assume this is some sort of load balancing/spreading algorithm.

Certainly never saw this particular outage before during my 15 years
in the industry.

Thanks all.

- Cary Wiedemann
--Misc Networking Engineering guy

-- 
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