I have a fairly large network with multiple locations that include a large amount of Cisco Meraki networking equipment. I have been struggling with some odd behavior at one of the locations. When Querying the IP address from within a web browser using the “$_SERVER[‘REMOTE_ADDR’]” at only one of the many locations, it always returns the same IP address that is assigned to one of the VLANs on the MX firewall. It’s not even on the same subnet. It just always shows that same IP. After doing some troubleshooting, everything was indicating that this was usually because of a proxy. But, we have no proxies in the network. I suspected it was related to the MX, but at first glance there was nothing that looked like a setting for a proxy.
It was not affecting any other systems, so I moved on to bigger issues.
Now, we needed to setup the Meraki MX to connect to a 3rd party VPN peer. Again, only at this location did I have trouble. All users that were going to specific websites over this VPN tunnel were getting the error of “Internal Error: Missing Template ERR_CONNECT_FAIL“. More research on this error also mentioned a proxy as a possible culprit.
So, this time I dug through every setting and found something that isn’t documented as a proxy, but it seems this is what the Meraki may be doing.
Under Security Appliance –> Configure –> Content Filtering, there is an option for Web search filtering. This was set to enabled. Apparently when this is turned on, it puts the web traffic into proxy mode. Turning it off solved my VPN trouble and the IP address identification from within the browser.
I figured I would share this in case someone else comes up against the same trouble.