Linux

Quick hack to get Munin to graph the cpu temperature.

First of all, install Munin and make sure it’s working.

Then follow these steps:

1. We’ll use cron to write the current temp to a log file. We do this because I wasn’t able to get Munin to directly execute the command (error: temp.value VCHI initialization failed)

Execute crontab -e and add this line (this has to be on one line):

5 or so days ago, this error suddenly popped up:

Unable to complete backup. An error occurred while creating the backup folder.

I have a Raspberry Pi, acting as TimeMachine (using afp/Bonjour/Netatalk).

There are several things I tried to solve this, including messing in the sparebundle from Linux (chowning) and deleting my TM .plist. This probably messed up my backup a bit.

But what seemed to ‘solve’ it for me was:

This.

I suddenly noticed issues with Postfix not accepting e-mails that are tagged (“user+TAG@fqdn”) anymore. Even though it always had.

Postfix main.cfg:

recipient_delimiter = +

Log snippet:

Apr 16 13:07:52 vm-dns-mail postfix/pipe[6119]: 55D1C2005E4: to=<user+test@rootspirit.com>, 
relay=maildrop, delay=0.06, delays=0.01/0/0/0.05, dsn=5.1.1, status=bounced 
(user unknown. Command output: Invalid user specified. )

Tried to find what’s wrong in MySQL, change the delimiter, Debug Maildrop, etc. Not much progress… :( And after 6 hours I was starting to get annoyed.

This.

Used my Raspberry Pi, with an USB disk as TimeMachine. Another disk as NAS/storage. It’s just quite slow… Not sure whether it’s my WiFi or RPi that can’t keep up.

But for now, it’s working.

For a few years I ran my own public DNS server. I liked it, great experience, I could easily connect all my host to a central and fast DNS, I avoided all those nasty ISPs who filter their DNS, and it was fast (not Google fast, but fast – I actually think Google DNS didn’t even launch when I set it up).

A good year or so, they started using the DNS server to DDoS others (spoofed UDP DNS requests). That’s annoying… It hit like 5k or so requests per minute… That wasn’t really fine, but I didn’t care much until I saw the traffic it ended up generating… Then I started to null route most IPs sending bogus DNS requests (spamming ripe.net or isc.org)… That usually worked, and for a whole time I didn’t get any more DDoS… Until, apparently, recently.

For no clear reason, OpenVPN on Mac with Tunnelblick (any version, had this problem for a few years already) results in these kind of error messages (and refuses to connect):

2013-02-05 17:44:31 write UDPv4: Can't assign requested address (code=49)
2013-02-05 17:44:33 write UDPv4: Can't assign requested address (code=49)

This seems to appear more often when swapping WiFi/IP range (after my Mac goes into sleep). But also happens when connecting to the same WiFi. It doesn’t change anything whether I disconnect OpenVPN before putting the Mac to sleep.

I now own three Raspberry Pi’s.

Using two of them (and my Guruplug as WiFi AP) I connected my new apartment with my old house (= parents) over VPN.

This way I can access the printers/scanners and NAS at home.

The 2 rPI’s are used as router (using a Macbook Air USB-to-Ethernet adapter as 2nd ethernet (eth1) port). Basic howto’s are easily found using Google to do this (a good starting point).