Asus RT-AX82U configuration

[#1]

Hi All,

Hoping someone can help me. I'm a new Plusnet customer, with FTTC. I am trying to get my Asus RT-AX82U working with my Hub 2 in bridge mode, but have run out of ideas. I would be grateful if anyone can suggest further troubleshooting steps.

I have entered my <username>@plusdsl.net and password into the PPPoE configuration (full settings given in the attached image), as described here: https://www.plus.net/help/broadband/broadband-connection-settings/. The router does not appear to have a VLAN option (as for some other Asus models), but some people seem to have modified these via the IPTV settings, which I've now configured to a VID of 101 (although have also tried left blank). 

The router shows 'The network cable is unplugged' in the network map, despite the Asus WAN port being connected to a Hub 2 LAN via RJ45. It is currently running Asuswrt-Merlin firmware, specifically 3004.388.6_0-gnuton1. I have upgraded the router's firmware to the latest version (previously running 388.2) as a troubleshooting step.

Everything works OK with the Hub 2 as a modem-router combo. In bridge mode, I have verified that the Hub 2 configuration/account details are fine, by using an older router - this connects correctly. I have also attempted to use the Asus router with an old BT OpenReach modem - this (as with the Hub 2 in bridge mode) does not connect. I have tried a variety of ethernet cables, and have independently verified that they work. I am therefore confident the problem lies somewhere with the router/router configuration.

I checked the WAN port itself by reassigning LAN ports (using the dual WAN functionality). Using a LAN as the WAN port also does not work, and any ports designated as WAN do not show the activity indicator lights when connected.

I think there may be some form of authentication issue, but this is not an area with which I'm overly familiar. The logs indicate:

<Date> <Time> pppd[XXXX]: Unable to complete PPPoE Discovery
<Date> <Time> pppd[XXXX]: Hangup (SIGHUP)
<Date> <Time> pppd[XXXX]: Terminating on signal 15
<Date> <Time> pppd[XXXX]: Exit.

but I'm unclear on how to resolve this. A prod in the right direction would be much appreciated.

[#2]

The router does not appear to have a VLAN option (as for some other Asus models), but some people seem to have modified these via the IPTV settings, which I've now configured to a VID of 101 (although have also tried left blank). 

You do not need any VLAN ID configured on the router, in fact it needs to be disabled. The Hub 2 in bridge mode will automatically insert any required VLAN ID.

The router shows 'The network cable is unplugged' in the network map, despite the Asus WAN port being connected to a Hub 2 LAN via RJ45.

Can you confirm that its connected to one of ports 1 to 3 on the Hub 2 ( not the red port 4 ) ?

[#3]

@MisterW thanks for your reply.

You do not need any VLAN ID configured on the router, in fact it needs to be disabled. The Hub 2 in bridge mode will automatically insert any required VLAN ID.

OK, thanks: I've disabled this, but there is no noticable change - i.e. the router still shows the network cable as unplugged, and the same errors appear in the logs.

Can you confirm that its connected to one of ports 1 to 3 on the Hub 2 ( not the red port 4 ) ?

Yes, I can confirm the configuration is Hub 2 LAN -> Asus WAN (i.e. it is not plugged into port 4 on the Hub 2). I've tried each of the LAN ports, just in case one of them was faulty/etc.

[#4]

@preate

I assume youve checked the cable , or tried another ?

TBH I'm not familiar with the Asus routers but just had another look at your configuration screenshot. You might want to disable the 'Enable VPN & DHCP connection' in the Special requirement from ISP section. Not sure what that is meant to be doing but it seems to be a bit similar to this (albeit quite old) post https://www.snbforums.com/threads/the-network-cable-is-unplugged-on-rt-ax88u-11.56524/page-2

If that doesnt work, then I'd try a factory reset

[#5]

Forget my comment about checking the cable, just re-read your original post and can see you've already done that

[#6]

Thanks @MisterW, appreciative of your efforts.

You might want to disable the 'Enable VPN & DHCP connection' in the Special requirement from ISP section.

Thanks, I have tried disabling this option, to no avail.

As a further troubleshooting step, I have re-flashed the router with the latest stock (rather than Merlin) Asus firmware (3.0.0.4.388_24232) and factory reset it. This still does not help, and I get a similar error in the logs, which appears to be the same issue:

<Date> <Time> pppd[XXXX]: Unable to complete PPPoE Discovery

<Date> <Time> pppd[XXXX]: pppd 2.4.7 started by <username>, uid 0

<Date> <Time> zcip client: configured <xxx.xxx.xxx.xxx>

The following error then repeats, which seems to indicate a issue with the connection to the upstream network:

<Date> <Time> pppd[XXXX]: Timeout waiting for PADO packets

I can also access the logs on the Hub 2, which yields the following:

<Date> <Time> Lan IPv6 Neighbour Discovery events: NEIGHBOR_SOLICIT

<Date> <Time> WAN Auto-sensing detected port DSL WAN

<Date> <Time> WAN connection WAN2_INTERNET_PTM connected

<Date> <Time> WAN Auto-sensing detected port DSL WAN

By contrast, just to get a point of comparison, taking the Hub 2 out of bridge mode yields:

<Date> <Time> WAN Sensing Auto sensing Complete, interface selected

<Date> <Time> WAN Sensing Auto sensing Running

<Date> <Time> Success - secondary DNS servers

<Date> <Time> Success - primary DNS servers

<Date> <Time> WAN connection WAN2_INTERNET_PTM connected

<Date> <Time> PPP: IPCP up

<Date> <Time> PPP IPCP Receive Configuration ACK

<Date> <Time> PPP IPCP Send Configuration Request

<Date> <Time> PPP IPCP Receive Configuration NAK

<Date> <Time> PPP IPCP Send Configuration ACK

<Date> <Time> PPP IPCP Receive Configuration Request

<Date> <Time> PPP IPV6CP Send Configuration Request

<Date> <Time> PPP IPCP Send Configuration Request

<Date> <Time> PPP: CHAP authentication succeeded

<Date> <Time> PPP CHAP Receive success : authentication successful

<Date> <Time> PPP CHAP Receive Challenge

<Date> <Time> PPP: LCP up

<Date> <Time> PPP LCP Receive Configuration ACK

<Date> <Time> PPP LCP Send Configuration ACK

<Date> <Time> PPP LCP Send Configuration Request

<Date> <Time> PPP: Received PADS

<Date> <Time> PPP: Sending PADR

<Date> <Time> PPP: Received PADO

<Date> <Time> PPP: Sending PADI

<a bunch of messages relating to 2.4G/5G setup>

<Date> <Time>PPP: Starting PPP daemon

<Date> <Time> WAN Auto-sensing detected port DSL WAN

<Date> <Time> WAN connection WAN2_INTERNET_PTM disconnected.[ERROR_NO_CARRIER]

<Date> <Time> WAN Auto-sensing detected port Ethernet WAN

<Date> <Time> Bridging is disabling

The Hub 2 logs are edited for relevance (although I can provide the full versions if useful). My takeway from all this is that the Asus router is not authenticating. As for why that is the case… I will continue digging.

[#7]

My takeway from all this is that the Asus router is not authenticating. As for why that is the case… I will continue digging.

@preate its not getting as far as authenticating.

<Date> <Time> pppd[XXXX]: Timeout waiting for PADO packets

When trying to make a PPPoE connection, the client will first send a PADI packet to try a discover a PPPoE server. If available , the server will respond with a PADO (service offer) packet, the client then sends a PADR and receives a PADS in reply. Only at this point does the client authenticate with the server. You can see this sequence in the Hub 2 log when its in router mode.

So your Asus thinks its sending PADI packets but is getting no PADO response. Given that you've tried an older router via the HUb 2 in bridge mode, it would point the finger at the Asus I'm afraid.

The Hub 2 log would indicate that its in bridge mode, but that should be confirmed by the LED being pink rather than blue ?

<Date> <Time> zcip client: configured <xxx.xxx.xxx.xxx>

I'm not sure what that is ?

edit: might be interesting to try a packet capture on the Asus WAN interface using tcpdump https://superuser.com/questions/1520625/capture-packets-on-asus-router

Perhaps it might be worth posting your current WAN config from the Asus first, also any dual wan settings

[#8]

When trying to make a PPPoE connection, the client will first send a PADI packet to try a discover a PPPoE server. If available , the server will respond with a PADO (service offer) packet, the client then sends a PADR and receives a PADS in reply. Only at this point does the client authenticate with the server. You can see this sequence in the Hub 2 log when its in router mode.

So your Asus thinks its sending PADI packets but is getting no PADO response.

Thanks @MisterW, this is a really useful primer, and gives me a starting point for further research. I will report back, if I find anything useful.

The Hub 2 log would indicate that its in bridge mode, but that should be confirmed by the LED being pink rather than blue ?

Yes, the light goes pink - it's definitely in bridge mode.

I'm not what that is ?

The xxx.xxx.xxx.xxx is in the format of a private IP address in the 169.xxx.xxx.xxx range (apologies: I removed it to be on the safe side, but in retrospect that was likely unhelpful). From what I can find, it's used by Asus routers when they cannot obtain an actual IP - which would make sense, if the PPPoE discovery process is failing.

[#9]

My query was more on what is a 'zcip cleint' rather than the IP

I'd done some edits on my previous post whilst you were posting the reply.

Perhaps its worth you posting the WAN and any DUAL WAN settings again...

[#10]

Just remembered this thread https://community.plus.net/t5/My-Router/What-s-the-cause-of-quot-Timeout-waiting-for-PADO-packet-quo... where the Asus doesnt seem to recover if a previous PPPoE session hasnt been disconnected cleanly.

Try connecting the old router that does work, then using that, Disconnect the PPPoE session before replacing with the Asus