I have just created a subnet for a local network, connecting to a standalone server on another network, now I cannot connect to the internet

Question

I am just learning some new aspects of servers and networking. We have a network of 5 subnets that all interconnect with each-other. In order to get two computers on the subnet that we were setting up, I changed the IP from the subnet where the standalone server is on (where they used to be set up)to the local subnet we are remotely hooking up. Likewise I also changed the gateway to coincide with the new subnet. Only problem is that since doing this, I am unable to establish a connection to the internet. I can ping the server and correspong gateway & DNS server, but cannot get connected to the internet. We do have a dumb-switch (non-programmable) connected that receives both the internet and private network inputs and distributes (or should do so) to about 5 other computers. Bottom line, I cannot currently connect to the internet, and am wondering what could be causing this.. It is likely something very obvious and pardon me being more vague than I probably should be, but I could use some help resolving this! Thanks for any help!

Answer 1

You may have a routing/packet filtering issue somewhere along the way. Since you can connect to peers on the LAN, but nothing from the WAN appears to be making it back to your new subnet, you likely have some kind of rule that is filtering traffic from a certain source.

Use traceroute (on Linux) or tracert on Windows to reach out and communicate with a few key nodes to see where the breakdown happens. I would suggest tracing to the server on your LAN, then your main internet gateway, then an internet address like www.Google.com or 8.8.4.4.

Ultimately, check your routers and gateways that make up the path for any rule that could be denying traffic from the internet.