Comcast Blacklisting IP Addresses

Hi, I'm a network technician for an ISP in the Tacoma area. We are currently seeing a large influx of calls over the last several days from customers stating that they are unable to access the Xfinity webmail page.

Customers are stating they receive the message "Temporarily blacklisted IP Address - try again later" when they attempt to access the site.

This only seems to be occurring on one of our two ASNs according to the calls we've received, though I'm currently unable to test thoroughly from the affected network.

We don't seem to have a point of contact for Comcast's NOC, so I'm posting here in hopes I can get the attention of someone who might have an idea of what's going on.

Regards,

Max