AC87U - DLNA and VPN Problems

[Thorton]

Bought AC87U 2 months ago, flashed 380.58 instantly (I'm on 380.59 now) and experience problems with it since the first day (did factory reset 3 times total, didn't help).


1st issue is DLNA - At least once a week, my Samsung TV can't access router (so I can't access content from HDD attached to the router). Solving it is easy - login to router, and re-enable (disable, then enable again) DLNA. While it's easy, it's also annoying. Just checked logs, no single word mentioning DLNA, so not sure what else to look for.


2nd issue is VPN client. Very often (2-3 times a week) Internet connection stops working on all devices (except IPTV on my Samsung TV, this one continues to work, so my guess is that router doesn't apply VPN on IPTV port, which is fine for me). Again, the solution is simple yet supper annoying - login to router and re-enable VPN client. Logs always show a truckload of this error - "openvpn[12252]: RESOLVE: Cannot resolve host address: europe.vpn.airdns.org: Name or service not known"


I know it's NOT VPN's problem because once I disable-enable VPN on router, it starts working the same second. Also, when Internet connection was down (because router couldn't connect to VPN) I tested VPN using my phone - disabled wifi and was able to connect to VPN (using EXACTLY THE SAME settings for VPN on router and phone) with my phone via mobile data without any problems.

 

[Thorton]

Internet offline again because "Cannot resolve host address". As always, disabling/enabling VPN somehow fixes the issue and router can connect to VPN server again. By the way, during downtime VPN Status window always shows CONNECTED, even if log says "Cannot resolve host address" and connection is actually down.

 

[john9527]

Internet offline again because "Cannot resolve host address". As always, disabling/enabling VPN somehow fixes the issue and router can connect to VPN server again. By the way, during downtime VPN Status window always shows CONNECTED, even if log says "Cannot resolve host address" and connection is actually down.

If you are using DNS mode exclusive, try changing it to strict. There can be cases where the VPN connection fails, but OpenVPN itself doesn't completely shut down and tries to reestablish the connection.. If you are using exclusive mode, you can get into a 'catch-22' where you can't reach the VPN DNS server to resolve the address.....and you also can't connect to the VPN to reach the DNS server.

The other possible workaround is to set up a postconfig script to turn off the 'persist-tun' option that is set by default (this should make the client really fail and restore your non-VPN DNS servers, but it may be incompatible with the block access if VPN is down option if you are using that). For example for client1, make a /jffs/scripts/vpnclient1.postconf with

#!/bin/sh
CONFIG=$1
source /usr/sbin/helper.sh

pc_replace "persist-tun" "#persist-tun" $CONFIG

EDIT.....Thinking out loud, maybe OpenVPN should automatically remove persist-tun in DNS exclusive mode.

 

[Thorton]

Thanks, will try it next time VPN connection fails (soon, I guess).

 

[Qbus]

Regarding 1st issue: try following solution http://www.snbforums.com/index.php?posts/260735

 

[Thorton]

"DNS config was set to "Disabled" in VPN client settings, changed it to "Strict" - no effect, still constant errors about unresolved hostname. Will try postconfig script now.

 

[Zirescu]

Sounds like you might be having DNS issues. Might want to try using a different DNS provider. The other thing to check is that the system clock on the router is accurate.

 

[Thorton]

If DNS is the issue, how it comes router can connect again the same second I re-enable VPN?

Also, how can the issue be related to clock? P.S. It's accurate.

 

[Zirescu]

I've seen the VPN fail to connect if the DNS servers used by the router cannot be reached or can't resolve the host name. Also, the VPN authentication will fail if the clock drifts too far off. Would need to see more log messages when the issue occurs to see if there is something that stands out.

 

[Thorton]

No more logs. The log file only contains hundreds of lines "openvpn[11287]: RESOLVE: Cannot resolve host address: europe.vpn.airdns.org: Name or service not known"

I clear the log, so it's empty, and when VPN failed again, no other text was available in the logs, except the one I quoted previously.