Feature: Track Nodes being IP Filtered

[gsxryan]

With the existing data collected, you would be able to identify and feature nodes that are being filtered (neighbors). This could help nodes troubleshoot or identify traffic issues compared to unfiltered neighbors.

1. Return all server address values
2. resolve DNS to IP addresses
3. filter only and sort by IP
4. create filter to detect duplicate IPs on the first 3 octet (x.x.x.y)
5. create a display page to show any nodes resolving to those duplicate prefixes

[3bl3gamer]

Since commit 11ad6e5 (and 3 more with fixes) there is additional line on each node page showing node IP and it's neighbor nodes count.

Still not sure what to do with IPv6-addresses (they are matched now by first three bytes too) and is it ok to reveal neighbor IPs/IDs (I consider them private so there is just a number now).