Month: February 2013

Dovecot – checkpassword – bash

The data from Dovecot’s checkpassword authentication mechanism can be read from a bash script via:

read -d $'\0' -r -u 3 USER
read -d $'\0' -r -u 3 PASS

NOCtools and OSS_SNMP Get Support for Multiple Spanning Tree (MST) Protocol

NOCtools (a mixed bag collection of tools and utilities for NOC engineers) and OSS_SNMP (a PHP SNMP Library for People Who HATE SNMP, MIBs and OIDs) have just gotten support for Multiple Spanning Tree.

Specifically, OSS_SNMP has two new MIBS (Cisco’s original MST tree which has a lot of deprecated nodes – MIBS\Cisco\MST; and the newer IEEE tree – MIBS\Cisco\SMST). With these, we can, for example, get an array of [instanceID] => instanceName values from a switch by just coding:

$ciscosw = new \OSS_SNMP\SNMP( $ip, $community );
print_r( $ciscosw->useCisco_SMST()->instances() );

NOCtools has the more impressive use cases of these new features. Specifically (and just likes its RSTP/pvrspt functionality), it can:

  • Show MST port roles (root, designated, alternate, etc) for a given (or all) MST instance(s) – this is equivalent to the RSTP version;
  • From a given device, it can crawl all CDP neighbours and create a graph of all devices, their connecting ports and the MST roles of those ports. This is a really useful feature as it means you don’t need to log into multiple switches to get a handle on what links are blocking. See documentation and a sample diagram here.

Irish Radio Stations on Linux (2013)

This is updating an older article from October 2010. While Linux has come a long way since then for playing back various types of media (and new services such as tunein make it easier again), I still like to just play the radio from the command line.

The following are updating working aliases:

alias newstalk='cvlc http://newstalk.fmstreams.com:8008/listen.pls'
alias rteradio1='cvlc http://av.rasset.ie/av/live/radio/radio1.m3u'
alias rteradio1extra='cvlc http://av.rasset.ie/av/live/radio/radio1extra.m3u'
alias 2fm='cvlc http://av.rasset.ie/av/live/radio/2fm.m3u'
alias todayfm='cvlc http://audiostore.todayfm.com/audio/todayfmIRL_64K.asx'

Git Tips From the Pros

I just came across some useful Git tips on a net tuts+ article  Git Tips From the Pros which includes:

  • Staging your commits in hunks;
  • Grabbing a file from another branch without changing branches;
  • Ignoring changes in a tracked file;
  • Zero-ing out a branches history; and
  • Some very useful aliases.

Synchronising Microsoft Exchange to Another IMAP Server

This post is much less of a detailed how-to but rather some useful links. We were tasked with the job of sync’ing about 1,000 MS Exchange mailboxes to a Dovecot server. This needed to be done via an administrator account on the Exchange end as individual user passwords were not available.

The tool of choice for this is imapsync.  Unfortunately, there is not a single formula that will work for all as it can depend on the Exchange configuration and version as well as the use of domains on the Exchange and ActiveDirectory servers.

To help understand the various combinations of logins for Exchange, I found the following invaluable: Understanding login strings with POP3/IMAP.

Also invaluable is the imapsync FAQ – just search for mentions of Exchange.

In the end, the following worked for me (but your mileage will most definitely vary!):

./imapsync --host1 exchange-server 
    --user1 'domain/adminuser/user' --password1 'admin-password' 
    --authmech1 LOGIN 
    --host2 dovecot-server --user2 user@example.com 
    --password2 userpassword

One key element here is that when logging into Exchange as an individual user I had to use --authmech1 NTLM but if you use this auth method with the above user string, you will always end up logging into the admin’s mailbox, not the user’s. That, at least, was my experience.

MySQL 5.6 – Memcached / NoSQL Support and More

MySQL 5.6 has been released with some interesting new features and performance increases:

  • What’s New in MySQL 5.6
  • DBA and Developer Guide to MySQL 5.6
  • InnoDB Integration with memcached:MySQL 5.6 includes a NoSQL interface, using an integrated memcached daemon that can automatically store data and retrieve it from InnoDB tables, turning the MySQL server into a fast “key-value store” for single-row insert, update, or delete operations. You can still also access the same tables through SQL for convenience, complex queries, bulk operations, application compatibility, and other strengths of traditional database software.

    With this NoSQL interface, you use the familiar memcached API to speed up database operations, letting InnoDB handle memory caching using its buffer pool mechanism. Data modified through memcached operations such as ADD, SET, INCR are stored to disk, using the familiar InnoDB mechanisms such as change buffering, the doublewrite buffer, and crash recovery. The combination of memcached simplicity and InnoDB durability provides users with the best of both worlds.

  • Multi-threaded Slaves
  • Improved IPv6 Support – both in the bind to address option and the INET_ATON() function.
  • Replication improvements.

All in all, some nice new features. Especially the memcached integration.

That said, MariaDB seems to be making inroads on MySQL with some distributions considering a switch. Some interesting reading from that project includes:

Woot! We hit 50Gbps at INEX!