Comcast "business" cable internet; blocking IPSec ISAKMP?

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View


Has anyone heard of this actually happening?  Googling it brings up a fair
amount of armwaving about this topic circa 2002, but nothing recently.

I have a client with this service at their remote office; their previous
IPSec setup was flakey and we replaced their firewalls on both ends with new
equipment, but when I installed this I've noticed that the tunnel cannot be
brought up with requests from their home office -- it appears that the
ISAKMP packets originating in the home office simply go nowhere.

But if the tunnel is brought up with keying initiated at the remote office,
it works just fine.  We verified this behavior by building a second tunnel
to the remote office from our office.

I can only think of two explanations for this phenomena:  Comcast is
deliberately blocking inbound ISAKMP packets to mangle IPSec tunnels, or the
cable modem itself has some filtering enabled, blocking these inbound
packets.





Re: Comcast "business" cable internet; blocking IPSec ISAKMP?



Quoted text here. Click to load it





Re: Comcast "business" cable internet; blocking IPSec ISAKMP?



Quoted text here. Click to load it

Take this to the Comcast hsi forum at www.dslreports.com .

Q




Site Timeline