IPv6 Peer Testing proposal

i2p2www/spec/proposals/126-ipv6-peer-testing.rst

+=================
+IPv6 Peer Testing
+=================
+.. meta::
+    :author: zzz
+    :created: 2016-05-02
+    :thread: http://zzz.i2p/topics/2119
+    :lastupdated: 2016-05-02
+    :status: Open
+
+.. contents::
+
+
+Overview
+========
+
+This proposal is to implement SSU Peer Testing for IPv6.
+
+
+Motivation
+==========
+
+We cannot reliably determine and track if our IPv6 address is firewalled.
+
+When we added IPv6 support years ago, we assumed that IPv6 was never firewalled.
+
+More recently, in 0.9.20 (May 2015), we split up v4/v6 reachability status internally (ticket #1458).
+See that ticket for extensive info and links.
+
+If you have both v4 and v6 firewalled, you can just force firewalled in the TCP configuration section on /confignet.
+
+We don't have peer testing for v6. It's prohibited in the SSU spec.
+If we can't regularly test v6 reachability, we can't sensibly transition from/to the v6 reachable state.
+What we're left with is guessing that we are reachable if we get an inbound conn,
+and guessing that we aren't if we haven't gotten an inbound conn in a while.
+The problem is that once you declare unreachable, you don't publish your v6 IP,
+and then you won't get any more (after the RI expires in everybody's netdb).
+
+
+Design
+======
+
+Implement Peer Testing for IPv6.
+
+
+Specification
+=============
+
+TBD, but basically, allow IPv6 addresses and connections in the Peer Testing protocol.