Comcast Static IP Changed With New Modem?

Mon Feb 9 16:48:09 UTC 2015

Yes, this is very common.  You are lucky to even get a working static IP
when they replace a modem.  A lot of times they forget to assign one or
assigned one that doesn't work.  No, most of the time they won't tell you
the IP changed.

Couple time I was told where my IP and default gateway wasn't in the same
subnet.  (example, static IP was x.x.x.4/30 and default gateway was
x.x.x.3).  Surprisingly, it didn't work.  It took me 30 minutes each time
to convince them that won't work.

On Mon, Feb 9, 2015 at 11:32 AM, Justin Krejci <JKrejci at usinternet.com>
wrote:

> Has anyone run into the situation where their static IP address from
> Comcast (on the business class cable modem Internet service) was changed
> when the modem was replaced?
>
> We have a remote site that uses Comcast as a backup Internet connection
> and when we went to use it recently our VPN tunnel would not establish.
> After working with the Comcast support group we discovered Comcast changed
> our static IP address. I am working through trying to figure out the when
> and the why with Comcast still and suspect it was changed when the modem
> was replaced back in December. The modem was replaced by Comcast as our
> previous modem was apparently EOL'ed.
>
> We're now setting up additional monitoring to verify the accessibility of
> our remote site via the Comcast connection so we don't have any future
> uh-ohs when we need to use our backup connection and it too is not fully
> functional.
>
> TIA,
> -Justin
>