RT-AX86U don't get proper WAN IP after power outage

[Incubus32]

I have a modem running on bridge mode and every-time there's a power outage my RTAX86U (version 386.7_2) gets a local WAN IP instead of a public IP.

It should be getting like this below. But the router stops doing the query once it gets an IP even tho a local IP which don't have internet access at all.

I have tried setting the DHCP query from aggressive to normal but still having the same issues.

I know the router do tend to restart faster than my modem. There's a easy fix tho, when I change any of the WAN settings, the router will have a successful query.

My problem here is when I am not at home, I can only do this when I am on my computer and with full access of my router's GUI.

Is there any script or add on merlin features that I can use to bypass this router's annoying behavior?

TIA!

 

[drinkingbird]

I have a modem running on bridge mode and every-time there's a power outage my RTAX86U (version 386.7_2) gets a local WAN IP instead of a public IP.

It should be getting like this below. But the router stops doing the query once it gets an IP even tho a local IP which don't have internet access at all.

View attachment 49783

I have tried setting the DHCP query from aggressive to normal but still having the same issues.

I know the router do tend to restart faster than my modem. There's a easy fix tho, when I change any of the WAN settings, the router will have a successful query.

My problem here is when I am not at home, I can only do this when I am on my computer and with full access of my router's GUI.

Is there any script or add on merlin features that I can use to bypass this router's annoying behavior?

TIA!

This is not uncommon when the router boots faster than the modem. In your case, the modem is first coming up in router (non-bridged) mode and handing out a private LAN IP. Then it downloads its config and changes to bridge mode, and that private IP is no longer usable.

Usually once the modem has downloaded its config it bounces the LAN port but obviously not always and not in your case.

Should be pretty easy to do with a script, you could do a manual DHCP renew, bounce the wan port etc. Any number of things will cause it to renew and get a valid IP.

Or if you don't want to get into scripting, just change the ISP device back to router/non-bridge mode and run in dual router/dual nat setup. Should not have any negative effects, if you need UPNP or port fowarding to work just put your router into the DMZ of the ISP router.

 

[Tech9]

This is not uncommon when the router boots faster than the modem. In your case, the modem is first coming up in router (non-bridged) mode and handing out a private LAN IP. Then it downloads its config and changes to bridge mode, and that private IP is no longer usable.

I've never seen anything like this happening on any of the modems I ever had.

 

[Incubus32]

This is not uncommon when the router boots faster than the modem. In your case, the modem is first coming up in router (non-bridged) mode and handing out a private LAN IP. Then it downloads its config and changes to bridge mode, and that private IP is no longer usable.

Usually once the modem has downloaded its config it bounces the LAN port but obviously not always and not in your case.

Should be pretty easy to do with a script, you could do a manual DHCP renew, bounce the wan port etc. Any number of things will cause it to renew and get a valid IP.

Or if you don't want to get into scripting, just change the ISP device back to router/non-bridge mode and run in dual router/dual nat setup. Should not have any negative effects, if you need UPNP or port fowarding to work just put your router into the DMZ of the ISP router.

Hey man thanks for the info! Though, I am not that good to do my own script. Maybe you could help me somehow what script to run

Changing the ISP back to non-bridge mode will be a huge pain for me. I have to call this with my ISP and takes a long period of time and sometimes they do mess up my speeds. If that happened, I have to call again and open a ticket to their support lol.

Thank you!

 

[drinkingbird]

I've never seen anything like this happening on any of the modems I ever had.

OP has a router, not a modem. Have seen it quite frequently with routers in bridge mode. They boot as routers, then get reconfigured as bridge when they download the config. If your router boots fast enough, it gets a private IP from the router mode, rather than public from bridge.

Old cable modems would actually do something similar when they had no WAN connection, they would hand out a private IP in 192.168.100.x so that you could access the modem GUI and troubleshoot. Not sure if they still do that.

 

[drinkingbird]

Hey man thanks for the info! Though, I am not that good to do my own script. Maybe you could help me somehow what script to run

Changing the ISP back to non-bridge mode will be a huge pain for me. I have to call this with my ISP and takes a long period of time and sometimes they do mess up my speeds. If that happened, I have to call again and open a ticket to their support lol.

Thank you!

You could try setting the Asus DHCP mode to Aggressive or Continuous DHCP and see if that makes it get the proper IP (and how long it takes). There is no pre-made script that I know of, you'd write one yourself.

 

[drinkingbird]

Hey man thanks for the info! Though, I am not that good to do my own script. Maybe you could help me somehow what script to run

Changing the ISP back to non-bridge mode will be a huge pain for me. I have to call this with my ISP and takes a long period of time and sometimes they do mess up my speeds. If that happened, I have to call again and open a ticket to their support lol.

Thank you!

Of course I ignored the real issue here - power outages. These devices are very easy to fry from frequent power issues. Invest in a cheap UPS and put both devices on that. Not only will it solve this issue, but it will protect your gear.

 

[ColinTaylor]

Old cable modems would actually do something similar when they had no WAN connection, they would hand out a private IP in 192.168.100.x so that you could access the modem GUI and troubleshoot. Not sure if they still do that.

Yes, I've seen this many times with all the various cable modem/routers my ISP has supplied. If the ISP side is slow bridging the public IP address it'll temporarily give out a 192.168.100.20 address.

 

[Tech9]

The ISP modem/routers I have or had in use all allow disabling Gateway functions in GUI and perhaps this is the difference. This is a local configuration. The ISPs with Web control of the device or the ISPs the user has to call for Bridge mode perhaps need to pull configuration settings after boot.