Articles in the system_administration category

1. Sendmail: Remove Queued Messages

   Posted on January 04, 2012 in system_administration

   for id in \`find . -mtime +10 -name qf\\\* \| sed 's/\^....//'\`; do
       mv qf\${id} /var/tmp/scott-20120104/ ;
       mv df\${id} /var/tmp/scott-20120104/ ;
   done
   

2. Lion + Cisco VPN DNS Workaround

   Posted on November 07, 2011 in System Administration

   When I upgraded to OS X 10.7 (Lion), I started using the built-in IPSec VPN client rather than Cisco's VPNClient. I experienced problems immediately. At first it appeared that the connection was being made, but no traffic was passing. When I tried pinging by IP address, I found that …

3. Mac OS X terminal and GNU screen scrollback

   Posted on October 11, 2011 in system_administration

   If you're a frequent user of GNU screen on your Mac, you are probably tired of using ctrl-a [ to enter scrollback mode. Adding the following lines to the .screenrc configuration file in your home directory in order to scroll with your mouse:

   defscrollback 5000
   termcapinfo xterm* ti@:te@
   

4. Killing Old popper Processes in Solaris 8

   Posted on September 19, 2011 in System Administration

   I've dealt with a few servers that have long lived popper (POP3) processes. These processes should be closed once the connection is closed, but they occasionally hang around. Once they get in this state, they will never close on their own. After a while, hundreds of these processes will just …

5. Sendmail Mail-to-Program Failures: Check smrsh

   Posted on September 05, 2011 in System Administration

   One of the beauties of using a Linux-based Mail Transport Agent (MTA) like Sendmail is the ability to pipe mail into programs. You can use this in conjunction with a filtering application like procmail, with a custom application that collects data about the email, or anything else you can imagine …

6. Cisco IronPort Default Username and Password

   Posted on August 26, 2011 in System Administration

   Why is it always a pain to find this stuff in the documentation?

   Username: admin
   Password: ironport
   

7. SNMP Traps into MySQL is Sublime

   Posted on August 22, 2011 in System Administration

   I use snmptrapd to catch SNMP traps and then put them into a MySQL database using a pretty generic trap handler. This gives me the opportunity to generate such useful information as:

   > SELECT HOUR(time) AS "hour", COUNT(*) AS "bounces" FROM snmptraps
       WHERE hostname = 'XXX' AND time > '2011-07-25'
           AND trap_oid …

8. How to Enable RPMforge-Extras

   Posted on July 25, 2011 in System Administration

   Historically, the RPMforge repository has aimed to create add-on RPMs for RHEL, CentOS, and Scientific Linux. Although their goal was not to replace base packages, avoiding that has not always been possible. In mid-November 2010, RPMforge created the rpmforge-extras and moved all packages that replaced base packages into the repository …

9. Installing Unison 2.27.57 via MacPorts

   Posted on June 13, 2011 in System Administration

   I've mentioned before that I use Unison to keep a few important directories synchronized between my various workstations and file server. I made the switch to Ubuntu 10.04 LTS recently, and started using its unison 2.27.57 package. This breaks all of my Macs that use unison 2 …

10. Limiting SSH Connections with ufw

    Posted on May 30, 2011 in System Administration

    In the past, I've written about the usefulness of using iptables to limit incoming SSH connections. Although it isn't a replacement for a good password policy, it at least limits the ability of outsiders to perform a brute-force password attack on your system. Now that I've started using Ubuntu more …