I configured a Cisco 2920 router for a Comcast Metro Internet circuit. The link is up and I have access to Internet, however after about 20 minutes the connection will drop.
The network layout goes:
Comcast hardware (Comcast tech said it's a switch) -> gig0/0 port on Cisco
My laptop is connected to the gig0/1 port
I made up the IPs in the attached config file, but this is what they represent
Comcast switch: 192.168.0.49/30
Gig0/0 on Cisco: 192.168.0.50/30
Gig0/1 on Cisco: 192.168.0.145/28
Static IP on laptop: 192.168.0.146/28
I have running pings going to 18.104.22.168, the Comcast box, gig0/0 and gig0/1 ports.
After about 20 minutes, I lose ping to 22.214.171.124 and to the Comcast box from the laptop.
To restore Internet I found that pulling out the cable between the Comcast and the gig0/0 port then plugging it back in immediately restores the connection, seems like a link down and then link up in the Cisco restores it. When this happens I also cannot ping the Comcast directly from the Cisco.
If I connect a laptop directly to the link on the Comcast and set the laptop's IP to 192.168.0.50/30 and gateway to 192.168.0.49 I get an IP conflict error and I cannot ping 192.168.0.49 or the Internet.
I want to rule out any Cisco configuration flaws before I go back to Comcast and tell them it's their configuration that's the problem.
I've attached the running configure with made up IPs and took out any extra config that I don't think is needed for this issue.