Strange things happening with GL-AR750S-Ext (Slate)

Hi everyone!

I am new to Gl.Inet brand but very much “not new” to networks. But what happened yesterday left me completely puzzled. I have the above router for few days planning to use it as a second router with LAN coming to my 2 laptops and WiFi for main/guest networks plus automatic failover to 4G via tethering in case my cable goes belly-up. So everything was configured, my main cable router was on 192.168.6.x subnet, new one configured for subnet 192.168.10.x plus more subnets for virtualisations, etc. Everything was working fine, until one day I have asked my ISP to increase the connection speed. They did it remotely but… changed my subnet to 192.168.2.x. And since then my Slate decided to connect to the ISP gateway directly ignoring primary router and switch. So it is competing with my main router, runs it’s own subnet and those two subnets don’t talk to each other. It looks like my main router is now a simple pass-through for Slate. I can change the gateway/IP manually - no problem. But just wondering if someone can shed a light on how that could have happened?

hi, welcome,

for the slate, what is the ip address for the wan and lan?

from the slate, could post the output of traceroute or from the web gui.

could be that your isp device was acting as a modem+router, and now that device was dumbed down to modem, also called straight thru bridge.
often done with voip and/or to prevent double-nat.

might try plugging a computer directly in the isp device and see what happens.

Thank you very much for your reply. I also thought that it might be something that my ISP did but it was difficult to get their tech people on Sunday. Strangely enough my NAS is connected directly to the ISP’s router and get it’s address on the first subnet. 192.168.1.x. My LAN for slate is set to but WAN, gateway and DNS all reside on external IPs. If NAS get it’s IP from the DHCP server on the ISP Router, I don’t understand what settings they are using. Actually they have told me that they will bring another 2.5G/5G router after the upgrade but haven’t done it yet. But the pass-through is definitely the case! While accessing NAS I now use loopback via Internet (Dynamic DNS), which is a very weird thing to do on a local network. I need to have a serious chat with my ISP, as downgrading equipment without telling the user is a very bad thing to do! Thank you very much for the idea! I will keep you posted when this thing has been resolved. In traceroute I don’t see any local IPs, so that is another sign that you are probably right. Just need to find out were my NAS gets its IP address or if I have any redundant DHCP on some of my equipment.

The good thing is: I like my Slate! It is not a nanny-router and with full access to Luci I can play with configs as much as I want. Recommended it to couple of clients already to solve office VPN problems for their Macbooks by delegating it to Slate. Both are happy now :slight_smile:

By default, the ISP modem/router “should” be in router mode because many/most customers do not have their own router. If the tech has bridged the modem/router during the upgrade, then a hardware reset (using external button) may switch it back to router modem, which is what happens to my ISP router.

Try rebooting your NAS, as it may have a previous DHCP lease.

I do not work for and I am not directly associated with GL.iNet

Thanks! The ISP is looking into it. The NAS recognizes as a gateway(?) and works on the loopback from Slate. My sons XBox also connected directly to the ISP router and it works. I should have DHCP running somewhere, could be my old auxiliary Linux box. And NAS has been restarted straight after that happened - no effect at all.

Maybe disconnect all devices and connect again.

Be sure that some devices are not working as dhcp server in your network.

Some of the subnets (mostly virtual) should stay on 24/7 :frowning: If I disconnect then it will be too much trouble reconnecting. I am just waiting for a dedicated router from my ISP as Slate acts as the only(!) router now and he does the job well. Just cant add a switch to it because I sometimes switch to the VPN. Today I had a very short (<1min) powercut but 4g failover kicked-in almost instantly and no connection was interrupted.

Hi Everyone and thanks for your help! The problem is solved. My ISP somehow (?) put one port on the cable router as pass-through, disconnected another port and left the 3rd port without DHCP. So the network was running crazy. Now I know which port does what and can very carefully reconfigure the routing table. That was tough! Can’t even think of the reason of doing it. I am now thinking of a new configuration with an extra subnet configured on passthrough with with loop on the main network - just adding another mini-router might solve this :slight_smile: