Can't ping default gateway but still connected to the internet.

[Phate]

Original Problem: Games became laggy, when I went to pingtest.net and ran a test, the Packet Loss test failed.

Fixes Tried:

- Contacted Comcast Customer Support, they reported a clean health check on my line, and restarted the modem a number of times.
- Power-cycling everything (of course)
- ran ipconfig /all, tracert to comcast.net, ping to Google as well as default gateway.
- Changed subnet mask of router to be 255.255.255.0, the same as what was displayed in ipconfig /all
- Tried to change DHCP settings to reserve 10.0.0.1, my "Default gateway". Was/is set to 10.0.0.2-10.0.0.200.
- Numerous google searches for posts of similar problems, couldn't find anything.

I think I've narrowed down the issue, I'm not certain why it's causing packet loss, but I can't ping my default gateway. Pings to any outside source work fine, pinging localhost works as well, traceroutes to XFINITY by Comcast -- Official Customer Site | Email | Watch TV Online work fine.

Below is the results of an ipconfig /all command on my machine:

Windows IP Configuration

   Host Name . . . . . . . . . . . . : Ander-PC
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : hsd1.il.comcast.net

Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix  . : hsd1.il.comcast.net
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 00-25-22-6C-88-96
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::c86b:81a5:ab2e:5a90%11(Preferred)
   IPv4 Address. . . . . . . . . . . : 10.0.1.16(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : Thursday, January 12, 2012 3:20:35 AM
   Lease Expires . . . . . . . . . . : Saturday, January 14, 2012 9:01:40 PM
   Default Gateway . . . . . . . . . : 10.0.1.1
   DHCP Server . . . . . . . . . . . : 10.0.1.1
   DHCPv6 IAID . . . . . . . . . . . : 234890530
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-55-61-1C-00-25-22-6C-88-96

   DNS Servers . . . . . . . . . . . : 2002:180d:9475:0:226:bbff:fe6d:58c7
                                       208.67.220.220
   NetBIOS over Tcpip. . . . . . . . : Enabled
   Connection-specific DNS Suffix Search List :
                                       hsd1.il.comcast.net

Tunnel adapter isatap.{E300D3AC-5897-4224-A067-44247032140B}:

   Connection-specific DNS Suffix  . : hsd1.il.comcast.net
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::5efe:10.0.1.16%14(Preferred)
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 2002:180d:9475:0:226:bbff:fe6d:58c7
                                       208.67.220.220
   NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter Teredo Tunneling Pseudo-Interface:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:1839:7467:e7f2:6b8a(Pref
erred)
   Link-local IPv6 Address . . . . . : fe80::1839:7467:e7f2:6b8a%15(Preferred)
   Default Gateway . . . . . . . . . : ::
   NetBIOS over Tcpip. . . . . . . . : Disabled

I'd be really happy if someone could help me resolve this problem, gaming is actually a source of income for me, and I can't play with this amount of packet loss.

-Phate