Added configuration example for rtrtr RTR server

Added some information on bird2 rpki and pre 2.0.8 limitaions
Added note for mikrotik router os v7

howto/Bird2.md

@@ -4,6 +4,13 @@ This guide is similar to the normal [Bird](/howto/Bird) guide in that it provide
 
 The `extra/bird` package in the arch repositories will usually have a relatively recent version and there is (usually) no need for a manual install over the usual `# pacman -S bird`.
 
+# Bird2 Version <2.0.8 / Debian
+
+Please note, that Bird2 versions before 2.0.8 don't support IPv6 extended nexthops for IPv4 destinations (https://bird.network.cz/pipermail/bird-users/2020-April/014412.html).
+Additionally Bird2 before 2.0.8 cannot automatically update filtered bgp routes when an used RPKI source changes.
+
+Debian 11 Bullseye delivers Bird 2.0.7. But you can use the Debian Bullseye backport-repository which provides version 2.0.8 (see https://backports.debian.org/Instructions/ for adding backports repository and install packages from the repository).
+
 # Example configuration
 
 Please note: This example configuration is made for use with IPv4 and IPv6 (Really, there is no excuse not to get started with IPv6 networking! :) )
@@ -171,6 +178,50 @@ include "/etc/bird/peers/*";
 
 The example config above relies on ROA configuration files in `/etc/bird/roa_dn42{,_v6}.conf`. These should be automatically downloaded and updated every so often to prevent BGP highjacking, [see the bird1 page](/howto/Bird#route-origin-authorization) for more details and links to the ROA files. 
 
+# RPKI / RTR for ROA
+
+To use an RTR server for ROA information, replace this config in your bird2 configuration file:
+
+```
+protocol static {
+    roa4 { table dn42_roa; };
+    include "/etc/bird/roa_dn42.conf";
+};
+
+protocol static {
+    roa6 { table dn42_roa_v6; };
+    include "/etc/bird/roa_dn42_v6.conf";
+};
+```
+
+... with this one (by changing address and port so it points to your RTR server)
+
+```
+protocol rpki roa_dn42 {
+        roa4 { table dn42_roa; };
+        roa6 { table dn42_roa_v6; };
+        remote 10.1.3.3;
+        port 323;
+        refresh 600;
+        retry 300;
+        expire 7200;
+}
+```
+To reflect changes in the ROA table without a manual reload, **ADD** "import table" switch for both channels in your DN42 BGP template:
+
+```
+template bgp dnpeers {
+  ipv4 {
+    ...existing configuration
+    import table;
+  };
+  ipv6 {
+    ...existing configuration
+    import table;
+  };
+}
+```
+
 # Setting up peers
 
 Please note: This section assumes that you've already got a tunnel to your peering partner setup.

howto/ROA-slash-RPKI.md

@@ -50,6 +50,30 @@ You can use these to simply run gortr via docker:
 
     docker run -ti -p 8082:8082 cloudflare/gortr -cache https://dn42.burble.com/roa/dn42_roa_46.json -verify=false -checktime=false -bind :8082
 
+### rtrtr
+
+rtrtr is a RTR server from NLNet Labs. It's compatible with the dn42regsrv ROA-JSON or burbles provided one (https://dn42.burble.com/roa/dn42_roa_46.json) too. 
+
+NLNet Labs provides an official docker image. You just have to bind mount a suitable configuration file:
+
+    docker run -d -v /etc/rtrtr.conf:/etc/rtrtr.conf -p 323:323/tcp nlnetlabs/rtrtr -c /etc/rtrtr.conf
+
+This is a working configuration file for dn42. Maybe change the listen addresses:
+
+    log_level = "debug"
+    log_target = "stderr"
+    http-listen = []
+    [units.dn42-json]
+    type = "json"
+    uri = "https://dn42.burble.com/roa/dn42_roa_46.json"
+    refresh = 600
+    [targets.dn42-rtr]
+    type = "rtr"
+    listen = ["0.0.0.0:323", "[::]:323"]
+    unit = "dn42-json"
+
+For more information cosult the official documentation: https://rtrtr.docs.nlnetlabs.nl/en/stable/
+
 ### Other tools / generators
 - bauen1's dn42-roagen: https://gitlab.com/bauen1/dn42-roagen
 - Kioubit's registry wizard:  https://git.dn42.dev/Kioubit/RegistryWizard

howto/mikrotik.md

@@ -22,6 +22,8 @@
 
 Mikrotik/RouterOS can't handle very well /32 on Point-to-Point links (like GRE). There is a [separate howto](/howto/mikrotik/ptp32) to explain how to setup /32 between in a GRE link (or even a OpenVPN). What is the easy way? Just use any /30 on the GRE Link, either from your assigned DN42 pool address or use a private address like 192.168. Please don't choose from 172.16.0.0/12 or 10.0.0.0/8 because they may overlap with DN42 or ChaosVPN.
 
+RouterOS v7.2 has some nasty bugs when using PTP configuration or IPv6 link local addresses as NEXTHOP. It won't work (confirmed for v7.2 by their support staff).
+
 ## Tunnel
 
 ### IPSec