content: Update documentation to contact server

As of 0.18, there should not be a need for port forwards for the
ipcpd-udp.

1 files changed, 47 insertions, 11 deletions

diff --git a/content/en/docs/Start/check.md b/content/en/docs/Start/check.md
index 69c5bef..494ee33 100644
--- a/content/en/docs/Start/check.md
+++ b/content/en/docs/Start/check.md
@@ -1,6 +1,6 @@
 ---
 title: "Check installation"
-date:  2019-12-30
+date:  2021-01-03
 weight: 40
 description: >
   Check if ouroboros works.
@@ -12,22 +12,18 @@ the [Tutorials](../../tutorials/) section, or you can try to ping this
 webhost over ouroboros using the name _ouroboros.rocks.oping_
 
 Our webserver is of course on an IP network, and ouroboros does not
-control IP, but it can run over UDP.
+control IP, but it can run over UDP/IP.
 
 To be able to contact our server over ouroboros, you will need to do
-some IP configuration: to tell the ouroboros UDP system that the
-process "ouroboros.rocks.oping" is running on our webserver by adding
-the line
+some small DNS configuration: to tell the ouroboros UDP system that
+the process "ouroboros.rocks.oping" is running on our webserver by
+add the line
 
 ```
 51.38.114.133      1bf2cb4fb361f67a59907ef7d2dc5290
 ```
 
-to your /etc/hosts file (it's the IP address of our server and the MD5
-hash of _ouroboros.rocks.oping_).
-
-You will also need to forward UDP port 3435 on your NAT firewall if
-you are behind a NAT. Else this will not work.
+to your ```/etc/hosts``` file[^1][^2].
 
 Here are the steps to ping our server over ouroboros:
 
@@ -42,8 +38,48 @@ daemon (ipcpd-udp) on that interface:
 $ irm ipcp bootstrap type udp name udp layer udp ip <your local ip address>
 ```
 
-Now you should be able to ping our server!
+Now you can ping our server:
 
 ```bash
 $ oping -n ouroboros.rocks.oping
 ```
+
+The output from the IRM daemon should look something like this (in DEBUG mode):
+```
+[dstaesse@heteropoda build]$ sudo irmd --stdout
+==01749== irmd(II): Ouroboros IPC Resource Manager daemon started...
+==01749== irmd(II): Created IPCP 1781.
+==01781== ipcpd/udp(DB): Bootstrapped IPCP over UDP with pid 1781.
+==01781== ipcpd/udp(DB): Bound to IP address 192.168.66.233.
+==01781== ipcpd/udp(DB): Using port 3435.
+==01781== ipcpd/udp(DB): DNS server address is not set.
+==01781== ipcpd/ipcp(DB): Locked thread 140321690191424 to CPU 7/8.
+==01749== irmd(II): Bootstrapped IPCP 1781 in layer udp.
+==01781== ipcpd/ipcp(DB): Locked thread 140321681798720 to CPU 6/8.
+==01781== ipcpd/ipcp(DB): Locked thread 140321673406016 to CPU 1/8.
+==01781== ipcpd/udp(DB): Allocating flow to 1bf2cb4f.
+==01781== ipcpd/udp(DB): Destination UDP ipcp resolved at 51.38.114.133.
+==01781== ipcpd/udp(DB): Flow to 51.38.114.133 pending on fd 64.
+==01749== irmd(II): Flow on flow_id 0 allocated.
+==01781== ipcpd/udp(DB): Flow allocation completed on eids (64, 64).
+==01749== irmd(DB): Partial deallocation of flow_id 0 by process 1800.
+==01749== irmd(II): Completed deallocation of flow_id 0 by process 1781.
+==01781== ipcpd/udp(DB): Flow with fd 64 deallocated.
+==01749== irmd(DB): Dead process removed: 1800.
+```
+
+If connecting to _ouroboros.rocks.oping_ failed, you are probably
+behind a NAT firewall that is actively blocking outbound UDP port
+3435.
+
+[^1]: This is the IP address of our server and the MD5 hash of the
+      string _ouroboros.rocks.oping_. To check if this is configured
+      correctly, you should be able to ping the server with ```ping
+      1bf2cb4fb361f67a59907ef7d2dc5290``` from the command line.
+
+[^2]: The ipcpd-udp allows setting up a (private) DDNS server and
+      using the Ouroboros ```irm name``` API to populate it, instead
+      of requiring each node to manually edit the ```/etc/hosts```
+      file. While we technically could also set up such a DNS on our
+      server for demo purposes, it is just too likely that it would be
+      abused. The Internet is a nasty place.
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