Make a diff!
If you ever need to quickly test an FTPS server, the CLI ftp client http://lftp.yar.ru is quite handy.
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)
Mac OS X comes with a pretty useful tool to list all the details about your system:
# system_profiler
E.g. to find out whether your RAM supports ECC:
# system_profiler|grep ECC ECC: Disabled
Or wether your SSD supports TRIM:
# system_profiler|grep TRIM TRIM Support: Yes
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:
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:
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).
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, 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:
More and more ISPs require customers to use the ISP’s own SMTP server for sending mail (to effectively block spam coming from hijacked customer workstations). Or you simply might want to send outgoing mail using your own SMTP mail server somewhere in the Internet, which should only accept encrypted, authenticated connection requests.
If you’re lucky, you can configure postfix on your Snow Leopard Server (and later) using the supplied ‘Server Admin’ GUI tool and enter your authentication credentials and the name of your (or your ISP’s) SMTP server there. This is explained in the following Youtube video: Using Your ISPs Mail Server in Snow Leopard Server.
In my case, this wasn’t sufficient, i.e. didn’t work and hence I had to use the CLI tool instead (which appears to be buggy, see later). The configuration of outgoing SMTP authentication for postfix on Mac OS X Snow Leopard Server is analogous to my quite old post about configuring SMTP auth for postfix on Linux, only the commands slightly differ.
Here are the commands I had to use:
# serveradmin settings mail:postfix:smtp_sasl_mechanism_filter = "plain"mail:postfix:smtp_sasl_mechanism_filter = “plain”
# serveradmin settings mail:postfix:smtp_sasl_security_options = "noanonymous"mail:postfix:smtp_sasl_security_options = “noanonymous”
# serveradmin settings mail:postfix:smtp_use_tls = "yes"mail:postfix:smtp_use_tls = “1”
The last command reveals a bug in the ‘serveradmin’ tool which will prevent postfix from working correctly as the value is set to “1” instead of “yes”! As a workaround, you need to manually set the value to “yes” in /etc/postfix/main.cf:
# vi /etc/postfix/main.cfsmtp_use_tls = yes
# vi /etc/postfix/sasl/passwd
# cat /etc/postfix/sasl/passwdsmtp.mydomain.com login:password
# postmap hash:/etc/postfix/sasl/passwd
# serveradmin stop mailmail:state = “STOPPED”
# serveradmin start mailmail:state = “RUNNING”
Done that, you can test the new settings by composing and sending a message using the ‘mail’ command:
# mail -s "a test message" myaddress@mydomain.com
(enter the body text and finish editing the message by entering a dot on an empty line)
Check the mail queue with
# mailq
Requeue messages that couldn’t be delivered using
# postqueue -f
[Edit 20130401: Fixed some typos, clarified the phrasing, anonymized data]
All in all, after several months of using it, I can strongly recommend the B & W Zeppelin Air. It’s a truly great iPod/iPhone speaker, filling even larger rooms with quite impressive depths and crisp heights. And in contrast to its competitors (e.g. think of the lousy hardware of the otherwise innovative Sonos speakers – what a pity!), you can see, feel and hear its excellent build quality. It’s been engineered by the guys who equip the famous Abbey Road Studios, supply the audio system for Jaguars and invented extravagant speakers like the Nautilus, after all.
The only thing which wasn’t satisfying so far, is the Zeppelin Air’s buggy default (software) implementation of Airplay, i.e. that the Zeppelin Air lost the Wifi connection after a while in stand-by mode. As I finally found out, all that’s needed to fix this is a firmware upgrade to version 2.00.24 [updated 20120930]. At least, my Zeppelin Air hasn’t ever lost its Wifi connection anymore since. So, if you experience Wifi connectivity issues with your Zeppelin Air (likely), don’t hesitate and upgrade the Zeppelin’s firmware now, although it’s somewhat cumbersome (you need a suitable USB cable, e.g. from an external hard drive or printer, as this isn’t included in spite of the Zeppelin’s upmarket price). It’s well worth it!