If you ever need to quickly test an FTPS server, the CLI ftp client http://lftp.yar.ru is quite handy.
Zimbra ZCS: OpenDKIM not running
After upgrading Debian, OpenDKIM sometimes stops running or fails to properly restart. If you don’t actively monitor your ZCS server, the only way to detect this is either through a growing mail queue of unsent messages or through a note in the ZCS server admin panel.
Usually, manually restarting either OpenDKIM itself or the whole ZCS server once “fixes” the problem:
# service zimbra restart
or
# /etc/init.d/zimbra restart
In other cases, fixing the permissions may help:
# /opt/zimbra/libexec/zmfixperms -verbose -extended
(source)
Some helpful Git resources
A friend recently told the following joke:
“The idea that git can be used offline is an illusion – you still need connectivity for googling which arguments to pass to what command.”
That’s an exaggeration, of course, but as always, there’s a grain of truth in it. So here we go:
- Probably the visually and didactically nicest Git reference I’ve seen so far: Git Reference at gitref.org
- Got 2 minutes for a quick introduction? Check Git for dummies!
- And of course, there’s the official Git Book with some more details.
Delete duplicate e-mail messages
If you need to delete duplicate e-mail messages on an IMAP server, take a look at this useful IMAP de-duplicator script:
IMAP de-duplicator – IMAPdedup
As IMAPdedup is a command line interface tool (a python script), it’s particularly useful for:
- automated deletion of duplicates (as it can be called from other scripts)
- extraordinarily big mailboxes or if you have many subfolders (as there’s no intervention by the user required)
- if you have console/shell access to the IMAP server (as you can then run the script on the server itself, speeding the de-duplication process further up)
I also found that it deals relatively well with failures (e.g. when a folder is read-only and hence messages can’t be deleted): It simply reports them on the screen and carries on.
Here’s a quick’n’dirty bash script to de-dup the inbox and all subfolders of the specified account:
#!/bin/sh # Delete all duplicate messages in all folders of said account. # Note that we connect through SSL (-x) to the default port. SERVER="my.server.com" USER="mylogin" PASS="mypass" for folder in `imapdedup.py -s $SERVER -x -u $USER -w $PASS -l`; do imapdedup.py -s $SERVER -x -u $USER -w $PASS $folder done
If you only have to de-duplicate messages in a small folder, you could also use the following de-duplication add-on for Mozilla Thunderbird:
Remove Duplicate Messages Add-on for Thunderbird
Note however that the ‘Remove Duplicate Messages’ add-on is intended for interactive use only, not for batch processing. I also noticed that it fails at cleaning big mail folders (e.g. containing 50’000 messages).
Moving Zimbra Collaboration Server to a new IP address
Here’s a quick overview how to migrate a ZCS mail server (based on Ubuntu) to a new IP address:
0) Not covered here: Adjusting DNS entries. Make sure you lower the TTLs of the relevant DNS entries a couple of days in advance in order to minimize downtime for clients (e.g. set a TTL of 300 for a 5 minute downtime).
1) Set the new IP address in:
* The relevant DNS entries
* /etc/network/interfaces
* /etc/hosts
* If ZCS runs in a container/VM, don’t forget to adjust its IP address too.
2) If the new IP address is part of a new subnet, make sure to add this new subnet to ZCS’s trusted_networks, otherwise, sending (relaying) messages through ZCS from Zimbra Desktop (or any other mail client) won’t work[1]. This can be set using ZCS’s web admin interface (i.e. https://mail.myserver.com:7071/zimbraAdmin/):
Navigate to “Server settings”, then open the “MTA” tab and set something analogous to the following in “MTA Trusted Networks”:
127.0.0.0/8 w.x.y.z/26
3) Restart networking and the ZCS services (it’s important, as this adjusts the trusted_network setting in ZCS’s amavisd too):
# /etc/init.d/zimbra stop
# /etc/init.d/networking restart
# /etc/init.d/zimbra start
Alternatively, just reboot the server, particularly if it runs in a VM.
Voilà!
Note: The need for the adjustments in step 2) might come as a surprise. Authenticated messages to be relayed through ZCS apparently seem to originate from the external IP address, not localhost/127.0.0.1.
[1] A typical postfix error message might look like:
Delivery Failure Notification: Invalid address: somebody . com.zimbra.cs.mailbox.MailSender$SafeSendFailedException: MESSAGE_NOT_DELIVERED; chained exception is: com.zimbra.cs.mailclient.smtp.InvalidRecipientException: RCPT failed: Invalid recipient somebody@somedomain.com: 554 5.7.1 : Relay access denied
iTerm2 – Mac OS Terminal Replacement
iTerm2, the successor of iTerm, seems to be quite a bit better then the default Mac OS X terminal app:
iTerm2 – Mac OS Terminal Replacement.
If only every Mac OS X app (i.e. Quartz) would also support copy on select, middle button paste and the other X11-like features! [1] Further, I’d love to see a terminal app that disallows pasting (cmd-v) from the keyboard-controlled clipboard completely as this is potentially a very dangerous thing.
[1] Note: It’s possible to emulate X11’s behaviour to some degree using BetterTouchTool. It’s still not the same though as X11 distinguishes between the mouse-controlled buffer and the keyboard-controlled buffer and doesn’t just “paste from the clipboard”. For reference, see:
Notes on tracing code execution in Django and Python « SaltyCrane Blog
Eliot from the SaltyCrane blog wrote a nice Django management command that allows to easily trace a Django runserver simply by executing ./manage.py trace runserver. Works great!
Django trace tool, django-trace is [..] a Django management command that uses sys.settrace with other Django management commands. https://github.com/saltycrane/django-trace.
via Notes on tracing code execution in Django and Python « SaltyCrane Blog.
Zimbra Collaboration Server: Best tested platform?
First: Of course, all listed supported ZCS platforms are tested platforms.
The interesting thing is that according to internal sources, most boxes in Zimbra’s test farm now run Ubuntu instead of Fedora/RH/Centos. Way to go, VMWare!
Zimbra Collaboration Server: Troubles after updating to ZCS 7.1.1 – here’s the solution.
Generally, Zimbra‘s update scripts for ZCS run smoothly. However, after updating ZCS from 7.0.1 to 7.1.1 on Ubuntu 10.04.2 LTS a couple of days ago, I noticed that most of the server’s services crashed within 1-2 hours after starting the (virtual) server.
To make a long debugging story short, here’s a summary of the problem:
The update script doesn’t properly remove old entries in /etc/rsyslog.conf when creating a new dedicated rsyslog configuration file for zimbra (/etc/rsyslog.d/60-zimbra.conf). This makes rsyslog log its own logging due to double rule entries – making /var/log/zimbra-stats.log grow at 2 MB/s. Like this, zimbra effectively DOSes itself as the server runs out of free disk space in no time (my above-average 12 GB of free space were filled within about 1 hour 40 minutes).
And here’s the solution:
1. Stop rsyslog to stop it from filling up your disk with nonsense: ‘/etc/init.d/rsyslog stop’ or ‘service rsyslog stop’
2. If necessary (i.e. if the updated server has been running for several minutes already), reclaim your free disk space by deleting/emptying big log files in /var/log, e.g. zimbra-stats.log, zimbra.log, mail.info, mail.log, mail.err, mail.warn etc.
3. Edit /etc/rsyslog.conf and remove the entries (likely at the end of the file) that look similar to these:
local0.* @mail.yourserver.com
local1.* @mail.yourserver.com
auth.* @mail.yourserver.com
local0.* -/var/log/zimbra.log
local1.* -/var/log/zimbra-stats.log
auth.* -/var/log/zimbra.log
mail.* @mail.yourserver.com
mail.* -/var/log/zimbra.log
(these are now in /etc/rsyslog.d/60-zimbra.conf)
4. Restart rsyslog: ‘service rsyslog restart’
5. Restart ZCS if it doesn’t run properly anymore: /etc/init.d/zimbra restart (you may even have to reboot the whole box if that doesn’t work)
Log.io – Real-time log monitoring in your browser
Log.io, real-time log monitoring in your browser powered by node.js + socket.io looks like a pretty useful project. I couldn’t check yet though whether it supports encrypted inter-server communication (often a must-have).