Asus RT A68U DNS and connection issues

[no1baggiesfan]

Log is still full of these errors, no idea what they mean tho:

May 10 18:51:27 openvpn[774]: WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1558', remote='link-mtu 1542'
May 10 18:51:27 openvpn[774]: WARNING: 'cipher' is used inconsistently, local='cipher AES-128-CBC', remote='cipher BF-CBC'

still losing connection every now and again, nothing in log

been on PC 40 minutes now, been disconnected 9 times, really starting to piss me off.

 

[Jack Yaz]

Turn off the VPN services for time being, see if any difference

 

[RMerlin]

Log is still full of these errors, no idea what they mean tho:

May 10 18:51:27 openvpn[774]: WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1558', remote='link-mtu 1542'
May 10 18:51:27 openvpn[774]: WARNING: 'cipher' is used inconsistently, local='cipher AES-128-CBC', remote='cipher BF-CBC'

still losing connection every now and again, nothing in log

been on PC 40 minutes now, been disconnected 9 times, really starting to piss me off.

Just ignore these, they are warnings that the pre-configured settings do not match the negotiated ones. Some providers will just mask these by adding "disable-occ" to the custom config section.

My guess is you are trying to use Cipher Negotiation while your remote server doesn't support it. Disable it, and add "ncp-disable" to the custom section (that option will no longer be necessary with 380.66).

 

[no1baggiesfan]

Turn off the VPN services for time being, see if any difference

the strange thing is, the VPN doesnt drop at the same time my pc does, it stays on, pc has dropped 9 times, vpn only dropped 3.
currently back on SH2, I need my connection

 

[Tuscon Bailey]

I'd like to take a crack at this. Some of this sounds similar to issues I had. Can you try the following:

1. Disable OpenVPN. Be sure it is not "Start with WAN" is not enabled. "Apply" the settings. Do not reboot yet.
2. Goto "Lan" -> "DHCP" -> Set "Forward local domain queries to upstream DNS" to "Yes"
3. Power Cycle Reboot

See if you keep a stable connection for a day.

If this works, goto the "VPN" tab and set-up a new OpenVPN profile (e.g., Client 2). Enable and monitor your logs. See if you maintain a stable connection. Let us know how it goes.

I had very similar issues that appeared to be associated with load on my router and a corrupt OpenVPN client config. I hope this is helpful.

 

[Jack Yaz]

There's no need for local domain queries to go upstream to the Internet.

 

[no1baggiesfan]

ok, I reflashed latest stock asus FW to router, powercycled/reset. it worked fine for 2 hours (no vpn)
so, flashed merlin 380.65.0 not the latest, stock settings, just my wifi and VPN settings changed, with VPN all seems fine so far, maybe latest is bugged ? or badflash ?

 

[Tuscon Bailey]

There's no need for local domain queries to go upstream to the Internet.

I agree. In my case I had unexplained DNS issues - nothing consistent just weirdness, that dissappeared when I enabled this option. No logic, just tried a few options. I reverted eventually to "No". Life is good.

Hopefully this rain dance helps the op...

 

[no1baggiesfan]

well, all was going well until tonight, had 2 disconnects in last 30 mins, TBH I am thinking its my VPN settings causing issues, log is full of warnings about VPN errors, VPN is working fine, but....... well, I thought it was sorted but its just as bad, online gaming is impossible, teamspeak drops every 5 mins, but still the VPN connection is solid, that device hasnt lost its connection, but all others have (2 phones, ipad (all 3 wifi) and PC (wired))

latest log:
May 11 21:00:52 disk_monitor: Got SIGALRM...
May 11 21:39:30 rc_service: httpd 439:notify_rc restart_dnsmasq
May 11 21:39:51 rc_service: httpd 439:notify_rc restart_wan_if 0
May 11 21:39:51 kernel: Attempt to kill tasklet from interrupt
May 11 21:39:51 miniupnpd[681]: ioctl(s, SIOCGIFADDR, ...): Cannot assign requested address
May 11 21:39:51 miniupnpd[681]: Failed to get IP for interface eth0
May 11 21:39:51 miniupnpd[681]: SendNATPMPPublicAddressChangeNotification: cannot get public IP address, stopping
May 11 21:39:52 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:52 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:53 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:53 rc_service: udhcpc 1344:notify_rc start_firewall
May 11 21:39:53 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:54 miniupnpd[681]: shutting down MiniUPnPd
May 11 21:39:54 start_nat_rules: apply the nat_rules(/tmp/nat_rules_eth0_eth0)!
May 11 21:39:54 wan: finish adding multi routes
May 11 21:39:54 rc_service: udhcpc 1344:notify_rc stop_vpnclient1
May 11 21:39:54 rc_service: waitting "start_firewall" via udhcpc ...
May 11 21:39:55 miniupnpd[1389]: HTTP listening on port 45867
May 11 21:39:55 miniupnpd[1389]: Listening for NAT-PMP/PCP traffic on port 5351
May 11 21:39:56 rc_service: udhcpc 1344:notify_rc stop_upnp
May 11 21:39:56 rc_service: waitting "stop_vpnclient1" via udhcpc ...
May 11 21:39:56 openvpn[822]: event_wait : Interrupted system call (code=4)
May 11 21:39:56 openvpn[822]: vpnrouting.sh tun11 1500 1561 10.86.10.6 10.86.10.5 init
May 11 21:39:56 openvpn-routing: Configuring policy rules for client 1
May 11 21:39:57 openvpn-routing: Tunnel down - VPN client access blocked
May 11 21:39:57 openvpn-routing: Adding route for 192.168.1.161 to 0.0.0.0 through VPN client 1
May 11 21:39:57 openvpn-routing: Completed routing policy configuration for client 1

 

[Tuscon Bailey]

ok, I reflashed latest stock asus FW to router, powercycled/reset. it worked fine for 2 hours (no vpn)
so, flashed merlin 380.65.0 not the latest, stock settings, just my wifi and VPN settings changed, with VPN all seems fine so far, maybe latest is bugged ? or badflash ?

If you can, move up to 380.65_4

well, all was going well until tonight, had 2 disconnects in last 30 mins, TBH I am thinking its my VPN settings causing issues, log is full of warnings about VPN errors, VPN is working fine, but....... well, I thought it was sorted but its just as bad, online gaming is impossible, teamspeak drops every 5 mins, but still the VPN connection is solid, that device hasnt lost its connection, but all others have (2 phones, ipad (all 3 wifi) and PC (wired))

latest log:
May 11 21:00:52 disk_monitor: Got SIGALRM...
May 11 21:39:30 rc_service: httpd 439:notify_rc restart_dnsmasq
May 11 21:39:51 rc_service: httpd 439:notify_rc restart_wan_if 0
May 11 21:39:51 kernel: Attempt to kill tasklet from interrupt
May 11 21:39:51 miniupnpd[681]: ioctl(s, SIOCGIFADDR, ...): Cannot assign requested address
May 11 21:39:51 miniupnpd[681]: Failed to get IP for interface eth0
May 11 21:39:51 miniupnpd[681]: SendNATPMPPublicAddressChangeNotification: cannot get public IP address, stopping
May 11 21:39:52 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:52 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:53 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:53 rc_service: udhcpc 1344:notify_rc start_firewall
May 11 21:39:53 openvpn[822]: write UDP: Network is unreachable (code=101)
May 11 21:39:54 miniupnpd[681]: shutting down MiniUPnPd
May 11 21:39:54 start_nat_rules: apply the nat_rules(/tmp/nat_rules_eth0_eth0)!
May 11 21:39:54 wan: finish adding multi routes
May 11 21:39:54 rc_service: udhcpc 1344:notify_rc stop_vpnclient1
May 11 21:39:54 rc_service: waitting "start_firewall" via udhcpc ...
May 11 21:39:55 miniupnpd[1389]: HTTP listening on port 45867
May 11 21:39:55 miniupnpd[1389]: Listening for NAT-PMP/PCP traffic on port 5351
May 11 21:39:56 rc_service: udhcpc 1344:notify_rc stop_upnp
May 11 21:39:56 rc_service: waitting "stop_vpnclient1" via udhcpc ...
May 11 21:39:56 openvpn[822]: event_wait : Interrupted system call (code=4)
May 11 21:39:56 openvpn[822]: vpnrouting.sh tun11 1500 1561 10.86.10.6 10.86.10.5 init
May 11 21:39:56 openvpn-routing: Configuring policy rules for client 1
May 11 21:39:57 openvpn-routing: Tunnel down - VPN client access blocked
May 11 21:39:57 openvpn-routing: Adding route for 192.168.1.161 to 0.0.0.0 through VPN client 1
May 11 21:39:57 openvpn-routing: Completed routing policy configuration for client 1

That WAN connection is an issue. Unfortunately I am not in modem mode so I don't have a way to troubleshooting more. I would lock down the WAN before working the OpenVPN client further as Jack Yaz suggested earlier.

A question if I may, do you have a computer that is using VPN s/w to connect to a network *and* are you using OpenVPN for other clients on your network? It works fine (personal experience) but I wanted to be clear. Also are you using policy based routing and routing the computer with VPN s/w accross OpenVPN?

Also noticed that you are still using OpenVPN client 1. I don't think it is an issue, but.. somewhere along the way maybe you can you disable profile #1 and create a new OpenVPN client profile under profile #2?

 

[no1baggiesfan]

ok, factory reset done
flashed to 380.65.4
factory reset again
wifi set up (wife and kids first)
VPN diabled for now (cancelled sub too, support never answered one of my 9 emails)

let the fun commence.

well, no drops so far, "he said"
also trying a new VPN service, they have proper asuswrt set up files and up to date confgs/certs.

 

[no1baggiesfan]

well, still getting drop outs, not as bad as last 2 days but its still happening, definitely gets worse when vpn is activated tho.

 

[no1baggiesfan]

sorry another post
problem is still happening, drop outs randomly happening, wife not happy either, apparently her ipad keeps getting kicked off the net for some weird reason, this stupid bloody router is going in the bin, I cannot understand how something so dam expensive can be such a dick to use, the SH2 was never this shirte, never had any problems with drops or wifi issues, this thing does it every 5 minutes.
Tried to change wifi settings this morning, guess what ? it wont let me log in now, im beginning to wish I had never bought the dam thing.

updated to newest FW again, cleared nvram, lets begin again.............

makes no difference what firmware I use lol, issue is still exactly the dam same, random disconnects (nothing in logs) wifes IPad gets chucked off wifi every now and again.
Ive read on the net that this might be an Asus router issue, might consider swapping to a netgear R7000, anyone have one ? before I go mental

 

[no1baggiesfan]

anyone have any ideas why this thing keeps dropping connection ?
its not just wifi its wired too, I have 6-7 devices and they are all losing connection ?
or do I just bin this router ?

 

[ColinTaylor]

The RT-AC68U is regarded as solid device. I've had mine for 6 months and it's connected to a SH2 in modem-only mode. It's been rock solid.

I don't use VPN's but from what you've said your problem seems to exist regardless of whether the VPN is running.

So from that I can only conclude that it's a hardware issue. See if you can get it replaced under warrantee.

 

[no1baggiesfan]

unit now replaced with R7000 NH
on holiday for a week now, so Im not messing with anything until I get back.
hopefully this new one works better than the dam asus did.

Thanks to all for help and advice.

 

[no1baggiesfan]

UPDATE.
lol, the NG R7000 worked for 2 weeks, had stock FW, tomato and merlin on it and I have to say, merlin does not like the R7000, the dropouts were similar to the N68U but never as bad, flashed from merlin back to stock and then flashed DD WRT kong on it, well, that killed it totally, it booted up but was not pingable , wifi never worked and even the fabled 25 second "backdoor" did nothing, long story short, it went back too, replaced with a new R7000, kong is now flashed and working 100%, not one dropout, no VPN issues, as much as I love the interface of merlin, I dont think its suited for the R7000.
end of this thread I guess
see you on the netgear threads

 

[ColinTaylor]

as much as I love the interface of merlin, I dont think its suited for the R7000

Tell it to the person that made the firmware - which isn't Merlin as he doesn't make firmware for Netgear's.

 

[ShadowRaven]

I’m having the same issue uberAC described.

I've had a long-standing similar issue with my AC68u. It loses it's ability to resolve DNS every few minutes. It only affects the 2.4GHz channel. It does not happen on 5GHz or ethernet connections. When running Windows Network Diagnostics, it generally reports a problem with DNS.


I found that I can use the Merlin firmware 378.54 and older and the problem does not occur. As soon as I update the firmware, whether Merlin or ASUS OE firmware, the problem immediately returns.


I've kind of given up battling it and bought and installed a new router yesterday -- no more woes.

The issue seems to appear randomly every 5-15 minutes on 2.4G only. The connection itself stays stable but it feels like there is just no traffic going on anymore. There won’t be an error or anything, everything simply stops loading. On Firefox on my Xperia Z5 I get the previously mentioned “DNS_PROBE_FINISHED_NO_INTERNET”. My router log showed this today after setting log level to debug:

Jan 14 16:01:24 dnsmasq-dhcp[473]: DHCPREQUEST(br0) 192.168.1.5 *******

Jan 14 16:01:24 dnsmasq-dhcp[473]: DHCPACK(br0) 192.168.1.5 *******Ethernet-Device

I have a cable modem in bridge mode and I’m not using VPN. I’m currently running Merlin 380.69 but before I’ve had various default firmwares before. I haven’t tried using 378.54 so far as downgrading this far can’t be the final solution.

I’ve had this problem for more than a year now and always though it might be caused by my phone because that was the only device I had to replicate it (I can now with my Surface Pro). I also didn’t bother too much as I simply worked around this by using 5G only. However now that my warranty has expired I find this thread proofing that I’m not the only one with this issue and now wish that I’d have returned it earlier.

I have tried setting "Lan" -> "DHCP" -> Set "Forward local domain queries to upstream DNS" to "Yes" what Tuscon Bailey suggested but I’ll have to do further testing.

I really hope that you can help me to fix this as it is a really annoying bug and as I can’t RMA anymore.

Edit:
"Forward local domain queries to upstream DNS" didn't work.
What's worth mentioning is that when I reboot the router everything works fine for like 20 minutes. Then the issue comes up more and more frequently the longer I use the 2.4 connection, up to about every 2 minutes. Another thing is that once this issue appears and nothing is loading anymore, waiting for about 2 minutes fixes it temporarily. Alternatively turning the wifi of my phone off and on again works too. Aditionally I've found more in the log:

Jan 14 19:33:12 dnsmasq-dhcp[471]: DHCPDISCOVER(br0) PHONE
Jan 14 19:33:12 dnsmasq-dhcp[471]: DHCPOFFER(br0) 192.168.1.195 PHONE
Jan 14 19:33:12 dnsmasq-dhcp[471]: DHCPDISCOVER(br0) PHONE
Jan 14 19:33:12 dnsmasq-dhcp[471]: DHCPOFFER(br0) 192.168.1.195 PHONE
Jan 14 19:33:12 dnsmasq-dhcp[471]: DHCPREQUEST(br0) 192.168.1.195 PHONE
Jan 14 19:33:12 dnsmasq-dhcp[471]: DHCPACK(br0) 192.168.1.195 PHONE android-a5fbc4ba611f233a
Jan 14 19:43:47 dnsmasq-dhcp[471]: DHCPREQUEST(br0) 192.168.1.4 DESKTOP
Jan 14 19:43:47 dnsmasq-dhcp[471]: DHCPACK(br0) 192.168.1.4 DESKTOP Desktop-PC

 

[ShadowRaven]

After clearing the nvram I really know nothing else I could try, which is really bothering me. Setting a static IP and Googles' DNS-Servers on my phone helps to some extent but doesn't fix it. I’ve found similar posts about ASUS routers having problems with DNS and I’m not sure whether this is a software related issue or if I have some faulty hardware.

@RMerlin could you take a look into this please? Or is this something related to ASUS/drivers you cannot fix?