AX88U behind ISP router- Internet drops/VPN/ISP DHCP does not function

[ppat]

Hello folks,

I am in definite need of some serious help with my new AX88U, please do read through what I have tried so far.

I am having internet drops (ASUS router status shows: "Internet disconnected"), and for some reason if it does manage to stay up for a while then it stops working with "Your ISP DHCP does not function correctly".

Somehow these two seem to be a more than usual occurrence and so yes I went through the following threads:

1. https://www.snbforums.com/threads/rt-ax88u-router-behind-modem-router-isp.67312/
2. https://www.snbforums.com/threads/rt-ax88u-internet-status-disconnected.67331/
3. https://www.snbforums.com/threads/a...-isps-dhcp-does-not-function-correctly.61902/
4. https://www.snbforums.com/threads/your-isps-dhcp-does-not-function-correctly.43178/
5. https://www.snbforums.com/threads/a...or-isps-dhcp-did-not-function-properly.61907/
6. https://www.snbforums.com/threads/new-rt-ax88u-no-wan-4-days-later.57960/

I was unable to come to a conclusive answer for this problem as some of these threads are not resolved and/or are going off topic now.

My intention with purchase of this router was similar reason as to thread 1 (handle VPN connection -PrivateVPN), use a hard drive in usb as a 'shared drive'. My problems are similar to above thread 3,4 and especially 6.


SETUP:
Internet -> Virgin(Bell) Valerie Modem/Router -> AX88U

Firmwares I tried with the settings below:

1. AX88U firmware upgraded to the latest ASUS. - NO INTERNET
(Rebooted manually/automatically every time I changed settings)

2. RT-AX88U_384.19_0 Asuswrt-Merlin. - CURRENT - NO INTERNET
(Rebooted manually/automatically every time I changed settings)


ISP Virgin Valerie modem/router:

does not have an exact "Bridge mode".
Advanced DMZ : I put AX88Us' MAC address.
DDNS: OFF
UPnP: ON
DLNA: ON
DHCP: ON (Router IP 192.168.2.1)
Port Forwarding: None
WPS: OFF
MAC Filtering: OFF
DNS: Automatically
WAN: Auto

AX88U Settings:

Adaptive Qos: OFF
OpenNAT Enable port forwarding: OFF
802.11ax / Wi-Fi 6 mode: Enabled
Wi-Fi Agile Multiband: Enabled
Target Wake Time: Enabled
Protected Management Frames: Capable
160 MHz: Enabled
WPS: OFF

LAN IP: 192.168.50.1
Subnet Mask: 255.255.255.0
DHCP: Enabled
IP Pool Starting Address: 192.168.50.2
Default Gateway: 192.168.2.1
Advertise router's IP in addition to user-specified DNS: YES
Enable Manual Assignment: NO
DNS Filter: OFF
IPTV: None

WAN Connection Type: Automatic IP
Enable WAN: YES
Enable WAN: YES
NAT Type: Symmetric

Enable UPnP: Yes
Enable secure UPnP mode: Yes
Enable WAN Aggregation: NO
Connect to DNS Server automatically: Yes
Forward local domain queries to upstream DNS :Yes
Enable DNS Rebind protection :Yes
Enable DNSSEC support : No
MAC Address Clone: Nothing (Tried using the LAN and WAN mac of AX88U here but no internet)
DHCP query frequency :Normal Mode
Extend the TTL value :Yes
Spoof LAN TTL value :Yes
Enable the DDNS Client :Yes

VPN: OFF
Have PrivateVPN client configured and worked somethimes VPN and internet(triple checked). But now no point without internet.

What am I doing wrong? Is it router or my understanding of settings is no bueno eh?
Kindly advise, please and thank you.

 

[L&LD]

See the M&M Config and the Nuclear Reset guides too in the link in my signature below to get your router to a good/known state.

Flash the firmware you want to use (I suggest going with 386.1 Beta 2 today). Complete the M&M process and change the settings as suggested. Do not use a saved backup config file to configure the router. Do not change settings willy-nilly. Only change one thing at a time and reboot, wait for the router to settle (about 5 to 10 minutes) and test again before changing settings again.

The following link may also be of help to determine if the firmware, settings, or the hardware itself is the issue.

Fully Reset Router and Network

 

[ppat]

Thank you. Given that I am having issues, would that beta firmware be advisable to use in my case? Or shall I flash it again following your steps using 384.19_0 Merlin?

End result wanted: good internet speed *with using VPN, use it to "share" my HDD via usb on router. (So NO double NAT is what I want).

My configuration of these two routers could have been wrong so after I follow your steps and router is back up with a new SSID etc then should I do anything or come back here and post what I am seeing and then ask for further steps?

 

[L&LD]

If you had flashed the RMerlin 384.19_0 and then did a full reset without using a saved backup config file, I see no reason to repeat those steps on that firmware from this past summer. Many things have changed since then.

What is good internet speed for you? What VPN are you using? Why do you think you need to use it?

What are you expecting to share and with how many concurrent users from the USB drive? A NAS is such a world of difference better (faster, more stable, and secure) than a USB connected/shared drive from a router's USB port.

Yes, I would do the steps suggested and with all working well, come back with any questions on how to proceed to achieve your expectations, then.

 

[ppat]

If you had flashed the RMerlin 384.19_0 and then did a full reset without using a saved backup config file, I see no reason to repeat those steps on that firmware from this past summer. Many things have changed since then.

I followed your steps and upgraded to the firmware RT-AX88U_386.1_beta2.

What is good internet speed for you? What VPN are you using? Why do you think you need to use it?

Consider me a level just above amateur but always wanting to learn. So whatever I am mentioning isn't necessarily how it should be or even right. Feel free to give me options and better way to do it. Pros/Cons but brief. (I'll find links from your signature)
Last speedtest on my ISP router shows about 60 Mbps download and 11 upload. I do not want to lose any further speed when I am connected to AX88 is what I meant. I am using PrivateVPN with details above.

What are you expecting to share and with how many concurrent users from the USB drive? A NAS is such a world of difference better (faster, more stable, and secure) than a USB connected/shared drive from a router's USB port.

Yes, I would do the steps suggested and with all working well, come back with any questions on how to proceed to achieve your expectations, then.

I agree from what I have been reading up and understand. But I also saw some fair points on why to avoid double NAS. First let's get my internet back up on this new one and see if it is hardware/me problem (while able to use VPN client, attach a usb drive and detect it, internet is stable and ON). I think that is a fair ask from a 400 dollar router which is built for it.
Internet -> Virgin(Bell) Valerie Modem/Router -> AX88U
I have now successfully brought the firmware to RT-AX88U_386.1_beta2, rebooted and followed all the steps you enlisted. ISP router wifi is up and running, AX88 is back to it's default state. (can see asus open networks).
Connected LAN cable into LAN1 of ISP router and WAN of AX88.
Connected phone to 5g but no internet because nothing is configured just yet. How shall I proceed next?

 

[ColinTaylor]

End result wanted: good internet speed *with using VPN, use it to "share" my HDD via usb on router. (So NO double NAT is what I want).

You said your ISP router does not have a bridge mode therefore it will be impossible to avoid double NAT. Double NAT will have no negative impact on speed or the VPN client.

As your ISP modem/router does not support bridge mode, go to the Asus WAN settings and clone the MAC address. Use the MAC address of the modem‘s interface into your wan port.

Don't do this. At best it would be pointless, but in all likelihood it will stop the connection between the ISP router and the Asus working properly.

 

[CaptainSTX]

Attached is an document explaining how to double NAT two routers.

As previously stated it will have no measurable effect on either your WAN or VPN tunnel's speed.

 

[dosborne]

Given that I am having issues, would that beta firmware be advisable to use in my case? Or shall I flash it again following your steps using 384.19_0 Merlin?

IMO, 384.19 and subsequent releases were causing a great number of issues, and often for AX88U owners specifically. I only go by what I was reading, but since 384.18 has been and continues to be solid for me, I was not willing to risk the potential instability. YMMV, and there are lots of opinions, but I would certainly suggest trying 384.18, but also ensure you follow the advice about resetting and manually configuring as that is very important.

FWIW, I have always run double (or triple) nat and have never had an issue related to it.

 

[ppat]

There were a lot of conflicting suggestions but here is what I have done now since flashing to the 386.1_beta2 last night:

Attached is an document explaining how to double NAT two routers.
As previously stated it will have no measurable effect on either your WAN or VPN tunnel's speed.

Thank you the document was useful and I followed directions.
The part where it says " On the LAN setup pick another subnet for this router to use. For this example I picked the subnet 192.168.75.0/24. " That is a mistake or am I thinking of subnet mask?
Either way I kept the default subnet mask 255.255.255.0 and now Internet is working! YAY!

But.

1. When I was connected to the VPN through the Client tab and streaming seemed slow (actual buffering). My download speedtest says about 63 Mbps on the speed test tab on QoS tab.
How to find out if it was the VPN provider/server I was connected to OR something wrong with my configuration?

2. Due to double NAT I see this on AiCloud and DDNS:
Kindly advise:

 

[ColinTaylor]

The part where it says " On the LAN setup pick another subnet for this router to use. For this example I picked the subnet 192.168.75.0/24. " That is a mistake or am I thinking of subnet mask?
Either way I kept the default subnet mask 255.255.255.0 and now Internet is working! YAY!

/24 is just another way of saying 255.255.255.0.

1. When I was connected to the VPN through the Client tab and streaming seemed slow (actual buffering). My download speedtest says about 63 Mbps on the speed test tab on QoS tab.
How to find out if it was the VPN provider/server I was connected to OR something wrong with my configuration?

Using a PC connected to the AX88U by Ethernet cable (not WiFi) do two speed tests, one with the VPN enabled and the other with it disabled. Compare the results.

2. Due to double NAT I see this on AiCloud and DDNS:
Kindly advise:

If you don't use either of those features you can ignore those warnings.

 

[CaptainSTX]

. When I was connected to the VPN through the Client tab and streaming seemed slow (actual buffering). My download speedtest says about 63 Mbps on the speed test tab on QoS tab.
How to find out if it was the VPN provider/server I was connected to OR something wrong with my configuration?

Depending on what you are trying to accomplish you may need to implement policy based routing so certain devices are not routed through the VPN tunnel. There are also options so that while a device is routed through the VPN tunnel certain services i.e. Netflix are not.

To determine what the maximum possible speed is on your VPN tunnel to a particular server download the VPN app from your VPN provider and test the speed with a wired connection to a PC and the VPN on the router off.

 

[ppat]

policy based routing so certain devices are not routed through the VPN tunnel

Where can I find the guide for it?

If you don't use either of those features you can ignore those warnings.

I would like to use the AiCloud for backup. And current DDNS will not allow me to access the router remotely?
Also now that I am on doubleNAT how do I port forward the PS, ports for torrent/tor?

 

[ColinTaylor]

I would like to use the AiCloud for backup. And current DDNS will not allow me to access the router remotely?
Also now that I am on doubleNAT how do I port forward the PS, ports for torrent/tor?

You never mentioned anything about AiCloud, "PS"?, torrents or Tor before.

DDNS can be setup on the Virgin router. You said that you already have the Asus in the Virgin router's DMZ to handle port forwarding.

 

[ppat]

You never mentioned anything about AiCloud, "PS"?, torrents or Tor before.

1. The HDD to the router that I was talking about would work with AiCloud backups.
Playstation, torrents and tor ports would not work?

2. policy based routing so certain devices are not routed through the VPN tunnel
Where are the settings for that?

you already have the Asus in the Virgin router's DMZ to handle port forwarding.

3. I do not. I was asked by a person on this thread to not do that so I removed it. Conflicting information got me confused, how do I implement all the above?

 

[ppat]

Also I am seeing this on the metrics page

 

[ColinTaylor]

1. The HDD to the router that I was talking about would work with AiCloud backups.
Playstation, torrents and tor ports would not work?

2. policy based routing so certain devices are not routed through the VPN tunnel
Where are the settings for that?


3. I do not. I was asked by a person on this thread to not do that so I removed it. Conflicting information got me confused, how do I implement all the above?

DDNS: Either set it up on the Virgin or the Asus. If you use the Asus you must use the "External" option as it states in your screenshot.

Port forwarding: Put the Asus in the Virgin's DMZ.

VPN speed: You never did the comparative speed tests that we asked you to do.

VPN Policy Based Routing: https://github.com/RMerl/asuswrt-merlin.ng/wiki/Policy-based-routing

You should leave these options at their default values:

Forward local domain queries to upstream DNS :No​

Extend the TTL value :No​

Spoof LAN TTL value :No​

That's it. If you still have intermittent internet drops look in the Virgin router's logs (not the Asus).

​

 

[ppat]

Asus you must use the "External" option

I configured to "External" and it accepted it without any problem! Although wasn't able to reach the address.

Port forwarding: Put the Asus in the Virgin's DMZ.

I did this now and the other settings you mentioned are also set to No.

The Wifi speeds are troubling:
Did something in the settings go backwards?

LAN cable to ASUS		PING ms	PING ms
		36​	35​
	DOWNLOAD Mbps	DOWNLOAD Mbps	DOWNLOAD Mbps
	62.41​	64.6​	62.25​
	UPLOAD Mbps	UPLOAD Mbps	UPLOAD Mbps
	11.26​	10.6​	10.81​
	NO VPN	VPN Through App	VPN on AX88U
WIFI	PING ms	PING ms	PING ms
	11​	34​	33​
	DOWNLOAD Mbps	DOWNLOAD Mbps	DOWNLOAD Mbps
	31.46​	35.35​	42.67​
	UPLOAD Mbps	UPLOAD Mbps	UPLOAD Mbps
	10.39​	10.75​	10.8 ​
Phone	12 / 64.7 Mbps / 11.1 Mbps	25/ 55 Mbps / 10.6 Mbps	11 / 63.8 Mbps / 11.1 Mbps

 

[ColinTaylor]

What is the difference between "WIFI" and "Phone"? Is "WIFI" a laptop? Are they both connecting over WiFi to the same band (2.4 vs. 5) and SSID on the router?

 

[ppat]

The Wifi was laptop which connected on the 2.4. Phone connected to the 5.

 

[ColinTaylor]

The Wifi was laptop which connected on the 2.4. Phone connected to the 5.

Then that probably explains why the laptop's speeds are that slow.