update README.md

README.md

@@ -10,7 +10,7 @@ First we start the container:
 
 ```shell
 docker run -d \
-	--restart=unless-stopped \
+	--restart=always \
 	--memory=256m \
 	--cap-add=SYS_ADMIN --cap-add=CAP_NET_RAW --cap-add=CAP_CHOWN \
 	--mount type=tmpfs,destination=/var/atlasdata \
@@ -22,10 +22,37 @@ docker run -d \
 
 Then we fetch the generated public key:
 
-```
+```shell
 cat /var/atlas-probe/etc/probe_key.pub
 ```
 
 [Register](https://atlas.ripe.net/apply/swprobe/) the probe with your public key.
 
+## Caveats
 
+### IPv6
+
+Docker's IPv6 support is still [like shit](https://github.com/moby/moby/issues/25407). As a workaround, you can use IPv6 NAT like this:
+
+```shell
+cat > /etc/sysctl.d/50-docker-ipv6.conf <<EOF
+net.ipv6.conf.eth0.accept_ra=2
+net.ipv6.conf.all.forwarding=1
+net.ipv6.conf.default.forwarding=1
+EOF
+sysctl -p /etc/sysctl.d/50-docker-ipv6.conf
+docker network create --ipv6 --subnet=fd00:a1a3::/48 ripe-atlas-network
+docker run -d --restart=always -v /var/run/docker.sock:/var/run/docker.sock:ro -v /lib/modules:/lib/modules:ro --cap-drop=ALL --cap-add=NET_RAW --cap-add=NET_ADMIN --cap-add=SYS_MODULE --net=host --name=ipv6nat robbertkl/ipv6nat:latest
+```
+
+Then start the RIPE Atlas container with argument `--net=ripe-atlas-network`.
+
+### Auto Update
+
+Use this recipe for auto updating the docker container.
+
+```shell
+docker run -d -v /var/run/docker.sock:/var/run/docker.sock --name watchtower containrrr/watchtower --cleanup --label-enable
+```
+
+Then start the RIPE Atlas container with argument `--label=com.centurylinklabs.watchtower.enable=true`.