Networking Woes

After changing ISP, I got a new modem with a built in wireless router. I managed to configure port forwarding and get it to work with my test server running on VirtualBox. Just for the record, the port forwarding interface on the device required me to select from a list of devices. I had to port forward to the host machine’s IP.

After some weeks of using the built in wireless router, I got tired of the weak signal strength. To be fair, it might be because it is placed in a less centralized location due to wiring constraints. I decided to connect my Linksys router to it and use the Linksys device for wireless service.

I had previously tried connecting a LAN cable from the local Ethernet port of the ISP provided modem to the WAN port of the Linksys device. That didn’t work at all. However, it does work when it’s connected to a LAN port on the Linksys device. I’m not sure why that’s the case as I thought putting it to WAN would just send all the packets through another layer of address translation.

Next step was to disable the wireless network on the built in modem and make sure that the Linksys router was configured with the desired settings. This was accomplished with the provided web administration interfaces.

When I tested the network, some devices could get Internet access, while some couldn’t. I had to disable and re-enable the wireless network adapter to get it to work.

Unfortunately, all these steps broke port forwarding to my guest OS. I had VirtualBox set up to use a bridged network, but it looked like the modem didn’t even recognize the guest as its IP did not show up in the list of connected devices.

I looked through the other network options in VirtualBox and looked up the documentation.

It turns out that with the NAT option, I could run a server on the guest OS if I configured port forwarding with VBoxManage. There’s even an example on the page.

Shut down the guest OS, change the networking option to NAT, and run the following command.

VBoxManage modifyvm "guest-name" --natpf1 "guest-https,tcp,,443,,443"

Restart the guest. As no IP address was specified with modifyvm, it is necessary to use DHCP on the guest. Change the networking settings, restart the eth interface, and try to access the web server.

A request to the web server now goes to the modem, where it is forwarded to the host machine, which then forwards it onwards to the guest! A little convoluted, but once again my test server is publicly accessible so I can ask friends for feedback.


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