Couple of weeks ago, I got knocked off the internet, and it took me awhile to figure out what when wrong.
Background –
I’m working with a new client and their application requires a high speed network to do what they want to do. So I finally had an excuse to purchase 1GB network equipment upgrade: a Network switch and a Network NIC.
I installed the switch and NIC without issue, and proceeded to “clean out” my Server.
I literally pulled all cables and took the machine out to the garage and used an air compressor to dust the beast out.
After the major dusting, in which clouds of dust escaped from the open garage, I also removed several unused PCI cards, and finally put things back together, and got the internal network running, but could not connect to the internet.
Issues –
I could connect to all my internal machines, but I could not connect from any machine out via Name.
Oddly, I could “ping” outside servers by IP address, but could not by Name, even when directly connected to the cable modem.
A couple of times, after hard resetting the cable modem and firewall/router, there would be access for a while, or be deathly slow.
Resolution –
I had to shut down shutdown the network, except for the main server.
Opened DNS manager and cleared any and all DNS caches, along with stopping and starting the server, and a reboot or two for good measure.
Then directly connected the main server to the “cable modem” via wired ethernet.
I changed the Server’s static IP address to be on the same sub-net as the cable modem (192.168.100.1).
Connect to OpenDNS, and delete the old IP information, and setup new IP information.
Reconfig the server back to it’s original IP range, connect firewall/router to modem, and reconnect to OpenDNS.
Finds –
I went through all my settings, machine by machine, flushed caches, renewed IP, reset WinSock, etc.
- Comcast has 1 hour DHCP address renewal
- Seems that when I had my server down for cleaning, it missed a DHCP “conversation” and my external IP changed.
- OpenDNS
- Was using my Old IP address and for some reason would not resolve IPs to Name.
Lessons Learned –
Since I originally ran into this issue, it has happen one more time, but I immediately connected the server to the cable modem, reestablished OpenDNS connectivity, and moved ethernet cables back. (Estimated time: 10 minutes vs. Hours of Troubleshooting)
I have also downloaded and installed the OpenDNS agent, and is running all the time.