The collecting ripsender ICMP data is available for you to look at on the web site in file /private/gwlog.txt. It has as the last two columns the ICMP type and code, so 'port unreachable' (code 3) can be distinguished from 'host unreachable' (code 1), 'net unreachable' (code 0), and 'protocol unreachable' (code 2), etc. I'm currently recording all 16 kinds of 'unreachable' in that file.
The amprgw daily gateway statistics files show the number and size of all sent and received traffic for each subnet and gateway, and the age of the route. It should be quite possible to analyze these and find gateways that aren't sending any traffic to amprgw. Of course, there can be gateways such as the one in Germany which uses asymmetric shortcut routing so it never does send any traffic to amprgw even though it's quite active. These files are available via the web server as eg, /private/gwstats.17-05-16.txt.
You're quite right that it's not an easy task to determine whether a gateway deserves to be removed from the portal's encap list. I believe it will take the combination of several factors before that decision can be made. Collecting statistics toward that end is the first step; we can't make decisions without data. - Brian
On Wed, May 24, 2017 at 09:41:19AM +0200, Rob Janssen wrote:
Of course another (not exclusively deciding) check on gateway activity could be to check if you actually receive any tunneled packets from them. I do have that as a byproduct of having an access list that accepts protocol 4 traffic only from addresses of registered gateways. At the moment it shows traffic from 34 different gateways (including amprgw). Of course, when the external address of a gateway changes, its history is lost.