I have 2820n working (sort of) in a trial M2M app with only Orange 3G E1752 in WAN 2, nothing in WAN 1. Despite good site reception the 3G drops if inactive--as usual! We use DynDNS to regain site but would like to lessen drop-outs without £££s for fixed IP and then ony 4mb/mth.
I can see in manual where you can set up ARP or ping for WAN 1 but even though it shows this feature in the pdf for WAN 2 it is not in the options list when WAN 2 set for 3G Any advice, tricks or tips would help, or am I overlooking a click box somewhere? Or can you set up dummy WAN 1 & sort failover routine to get 3G on & the ping transfers from 1 to 2 ??
Ideally you don`t want to keep pinging the outside world or it gets expensive but apparently you can tickle the Sim to keep it awake.
We hope to add a SCADA PC to the Vigor but reluctant until stable comms.
I was told a similar feature provided on Teltonika RUT105 but not convinced this is ideal method either--attached para 4.9.2

""4.9.2 Ping Reboot
The Ping Reboot feature allows rebooting the router if the connection to GSM network is lost.
This feature checks (using ICMP echo request, like ping utility) if specific hosts are accessible on the network. Function allows adding several host IP addresses. When at least one server does not respond the router is rebooted if the check box “Enable reboot if no echo received”.
Enable – check the box to enable Ping Reboot feature.
Ping interval – specify the monitoring time period in seconds
Retry count – specify the number of failed reach ability checks
Enable reboot if no echo received– enable reboot the router if no echo to sent ICMP requests is received.
IP address – Set the host IP address to which ICMP requests will be sent.
Add – Click to add host IP.""

Forgot to say: firmware 3.3.4_232201_A Hardware:Annex A

Since no one else has been able to comment could DrayTek please confirm or refute WAN 2 ability to ping if set as 3G. N.B. nothing in WAN 1.
Thanks in anticipation

You can, the option isn't in the web interface though - you'd need to do it through telnet. The two commands you would need to enter in there are:

wan detect wan2 target 8.8.8.8
wan detect wan2 on

The first command sets the target IP (in this case 8.8.8.8) and the second command enables ping detect. You should see the WAN2 LED on the router flash periodically now.
That should act as a keep-alive and make the router more aware if the connection drops so that it can re-establish quicker.

Ta, I`ll try that when next at site unless you think its ok to Telnet over flakey 3G ?? Not sure I could figure Telnet through a browser--more beer needed!
Ta Ta

If you've got remote management enabled on the router, it should be fine to telnet to it, telnet sends such a tiny amount of data that it'll often be usable when http isn't.

Voodle,
thanks for the previous Telnet info which I implemented on 13th Aug and it does what it says on the tin. We can now remote log-in to our data gatherers quickly & have far fewer changes of IP or lock-outs.
Over the 3 weeks I have been checking my usage on the 3G (using the traffic graph tool) and estimate that the ping portion is about 19 / 20mb per day, does this seem about right & if so is there a Telnet instruction to reduce the ping frequency / usage slightly?
Is the default period for your previous command about 3 minutes?

Thanks in anticipation
Even Baldierdad