For two months, a client of mine loses Internet connectivity 3-5 times a week for a few minutes to around an hour. During an outage, we cannot ping known-good external IP addresses like 126.96.36.199, 188.8.131.52, 184.108.40.206 and 220.127.116.11 let alone external host names.
I've pestered Comcast as I was postive it was their issue. However, we found last week that if during an outage we jump on the Comcast modem's web interface and ping, say, 18.104.22.168 from it, we get responses yet other devices on the LAN cannont successfully ping the same IP address. If we wait long enough, connectivity returns.
Here's what we've tried:
1. Replacing the modem
2. Taking the ASA 5505 out of service
3. Replacing the only switch.
- when one computer fails to reach the Internet, all computers fail.
- Intra-LAN communication never falters.