ASUS router with Starlink - conflicting WAN IP

[Wrkdbf_Guy]

Note: probably this is not technically an ASUSWRT-Merlin question, but since I am happily running that firmware, posting here just in case.

In an effort to reduce my ISP cost, I recently installed Starlink (SL) and have been testing it for the past few days. No problems accessing and using SL wifi. BTW my current/old ISP is via a Cable Modem (CM).

Now I am trying to move one step forward in my testing and set the SL to "Bypass" mode so I can use my existing ASUS wifi network, which has far more functionality. I am using this ASUS FAQ to set up bypass mode, which is straightforward enough. But when I move over the Ethernet cable from my CM to SL, the ASUS router complains of an IP conflict with the SL's WAN IP (192.168.100.1). The CM uses the same IP 192.168.100.1.

How can I get the ASUS router to "forget" the CM WAN's use of IP 192.168.100.1 so SL can use it? Or should I be trying to let the ASUS router reassign the conflict to a new IP? I would have expected the Ethernet cable move to cause the IP to move as well.

Bill

 

[Galaxysurfer]

Maybe this will help? I am not a current Starlink user.

https://www.gearrice.com/update/how...uters-with-starlink-and-improve-wifi-at-home/

 

[ColinTaylor]

I can't think why you would be getting an error when you move the cable from the CM to Starlink. Unless you have changed the Asus' LAN subnet to be 192.168.100.x.

 

[Wrkdbf_Guy]

I can't think why you would be getting an error when you move the cable from the CM to Starlink. Unless you have changed the Asus' LAN subnet to be 192.168.100.x.

No, the LAN Subnet has not been changed.

 

[Tech Junky]

MAC doesn't match. Just like when you switch devices connecting to the CM you need to reboot the CM to get an IP. In this case though rebooting the Asus should clear the IP issue since it's more than likely the MAC mismatch w/o a reboot.

 

[Wrkdbf_Guy]

... rebooting the Asus should clear the IP issue since it's more than likely the MAC mismatch w/o a reboot.

This makes some sense. I will try a router reboot early some upcoming morning and see how that goes. Can't try it now since the family is up and using the network. Don't want a Revolution. grin

 

[Tech Junky]

Revolution

Tell them it's important to test SL and make sure it's working before you're locked into not being able to return it if it's not working. IIRC you paid ~$600 for the setup HW alone? OR if you've already tested it with a laptop or PC and know it's working fine give them some cash and tell them to go get some food somewhere which should buy you 30 minutes to reboot and confirm things are working fine.

 

[Wrkdbf_Guy]

Well, the ASUS router reboot didn't help/work. Even after two reboots and a power cord disconnect (for 10 minutes), It still recognizes a duplicate WAN IP address when the router comes back up - all this with the Cable Modem completely disconnected from the ASUS network.

 

[ColinTaylor]

Well, the ASUS router reboot didn't help/work. Even after two reboots and a power cord disconnect (for 10 minutes), It still recognizes a duplicate WAN IP address when the router comes back up - all this with the Cable Modem completely disconnected from the ASUS network.

Can you show us a screenshot of this error message?

 

[Wrkdbf_Guy]

The ASUS Router Gui shows this.

Then if I click on that message, the following error details are displayed. It suggests I change the IP.

 

[ColinTaylor]

Thanks. That suggests to me that the Starlink device is using 192.168.1.x for the WAN. Maybe it also creates 192.168.100.x in addition to that for admin purposes, the same as some cable modems do. So the solution would be to change the Asus' LAN from 192.168.1.x to 192.168.2.x (or something else of your choosing). - Or just click next in the GUI to let it do that for you.

 

[Wrkdbf_Guy]

The conflict is with the 192.168.100.1 address. And I don't really care to change any (working) LAN ranges on my main ASUS router.

I'm thinking what I might do is take my mesh AC68U and do a full Factory Reset on it. This will certainly lose any stored WAN IP's - and all other IP's of course. It will also take it out of mesh mode and put it into default wifi mode. Then I will ethernet plug that into the Starlink and the AC68U will see a new WAN link from the SL.

Of course, all of this will have me reentering all my router settings from scratch. But at least I should then be able to proceed with testing the SL in Bypass mode with the ASUS router running all wifi.

 

[ColinTaylor]

The conflict is with the 192.168.100.1 address.

Why do you think the conflicting address is 192.168.100.1? That message normally refers to a conflict with the LAN subnet. You said earlier that you hadn't changed the LAN subnet so I'm assuming it's 192.168.1.x. So I would expect that to be the conflicting address.

EDIT: The first thing that turned up in a Google search was this blog post. In it he describes how the default IP address of the SL is 192.168.1.x. However, when he enabled bypass mode he got a CGNAT address instead (100.77.n.n). So perhaps you haven't enabled bypass mode on your SL?

 

[Wrkdbf_Guy]

So perhaps you haven't enabled bypass mode on your SL?

That's what I'm trying to do. But until the SL senses a good connection to the Asus router via Ethernet, it doesn't allow the Bypass mode to be saved. The IP conflict is getting in the way.

 

[ColinTaylor]

That's what I'm trying to do. But until the SL senses a good connection to the Asus router via Ethernet, it doesn't allow the Bypass mode to be saved. The IP conflict is getting in the way.

Can you plug a PC/laptop into the SL instead of the router. Then enable bypass mode and save it. Then power it off, swap over to the Asus, and then turn everything back on.

 

[Morris]

Can you plug a PC/laptop into the SL instead of the router. Then enable bypass mode and save it. Then power it off, swap over to the Asus, and then turn everything back on.

After connecting the PC/laptop, please display the IP Starlink assigned to the computer. If it is the same as your internal network, then you have two choices:
1) renumber as the Asus router suggests
2) leave the SL in NAT mode and run double NAT

 

[ColinTaylor]

2) leave the SL in NAT mode and run double NAT

It's the default NAT mode that's creating the conflict.

 

[Morris]

It's the default NAT mode that's creating the conflict.

I see nothing that indicates that SL is providing publicly addressable IPs for the wan interface of the Asus router when not in NAT. It needs to be checked.

 

[ColinTaylor]

I see nothing that indicates that SL is providing publicly addressable IPs for the wan interface of the Asus router when not in NAT. It needs to be checked.

Neither do I. According to that blog post I linked to when not in bypass mode it acts like any other wireless router, with a LAN of 192.68.1.x (which is creating the conflict). When in bypass mode the customer's router gets a CGNAT address. So either way there's double NAT happening.

EDIT: Appears to be confirmed here.

 

[Wrkdbf_Guy]

Can you plug a PC/laptop into the SL instead of the router. Then enable bypass mode and save it. Then power it off, swap over to the Asus, and then turn everything back on.

I can certainly plug my laptop into the Ethernet port and access 192.168.100.1. That brings up the SL app. But config changes are only allowed to be done via mobile - iOS or Android.