Hi, I am running 2 switches in my network right now configured like this:

Cable Modem---------HP ProCurve 2524 24 Ports<---------------gigabit
fibre-------------->HP ProCurve 2626 26 Ports-------Cisco PIX 506e
Firewall -------- Cisco 2621 Router

The cable modem is connected to port 1 of the 2524. I have currently 4 VLANs
configured on the switches, 1 is for the Cable ISP, 1 is for my internal
LAN, and another for a wireless bridge, and another for the DMZ. Both of the
switches are running VLANs through GVRP, and periodically advertises CDP
announcements. Now I am wondering if it is possible that if another node on
my cable network can hook up a simular switch to their modem and then pickup
the GVRP VLAN advertisments and be able to access my VLANs? I noticed that
the cable HFC is something like 10.68.192.0/20 or something.

The 2626 switch is located in the networking room and the internet ip is
brough to the cisco pix through the fiber since the networking room does not
have a cable jack.

Thanks!!