Category Archives: Admin

How to test if a web site requires a client certificate

Posted on June 20, 2019 by john | 3 views

Intro I can not find a link on the Internet for this, yet I think some admins would appreciate a relatively simple test to know is this a web site which requires a client certificate to work? The errors generated … Continue reading →

Posted in Admin, Linux, Network Technologies, Raspberry Pi, Security, Web Site Technologies | Tagged | Leave a comment

F5 clustering tips

Posted on May 1, 2019 by john | 26 views

Intro I was having trouble with one of my new F5 clusters. I thought I’d be clever and add two new F5’s to the existing cluster, and then remove the old members when everything looked good. But the device groups … Continue reading →

Posted in Admin | Tagged , , , | Leave a comment

Postfix Operational tips

Posted on April 3, 2019 by john | 22 views

Intro I’m trying out the system-supplied postfix on a SLES system. i had been using sendmail but there doesn’t seem to be any development on that software. Some commands I needed right away Well, right away I had thousands of … Continue reading →

Posted in Admin, Network Technologies | Tagged , | Leave a comment

How to add private root CAs in SLES or Redhat

Posted on March 18, 2019 by john | 28 views

Intro From time-to-time I run my own PKI infrastructure, namely issuing my own certificates form my private root CA. I wanted this root CA to be recognized by Linux utilities running on Suse Linux (SLES), in particular, lftp, which I … Continue reading →

Posted in Admin, Linux, SLES | Tagged , , , | Leave a comment

Fishcam using Raspberry Pi and some network tricks

Posted on February 3, 2019 by john | 43 views

Intro There are more articles about running a webcam using Raspberry Pi than Carter has pills. Why bother to create another? This one is unique insofar as I created a fishcam at a school with a restricted network. None of … Continue reading →

Posted in Admin, Linux, Raspberry Pi | Tagged | Leave a comment

The IT Detective agency: Live hack caught, partially stopped

Posted on January 18, 2019 by john | 32 views

Intro In my years at cybersecurity I’ve been sufficiently removed from the action that I’ve rarely been involved in an actual case. Until last night. A friend, whom I’ll call Jute, got a formal complaint about one of his hosted … Continue reading →

Posted in Admin, DNS, Network Technologies, Security | Tagged , | Leave a comment

Google Hangouts Meet – what do these IPs all have in common?

Posted on December 17, 2018 by john | 36 views

173.194.207.127 209.85.232.127 64.233.177.127 64.233.177.103 74.125.196.127 They all have been used by Google’s Hangouts Meet based on my observation. If you have an environment which uses proxy authentication, the above IPs do not play well with that. So you’ll need to … Continue reading →

Posted in Admin, Proxy | Tagged | Leave a comment

Great serial port concentrator: Raritan Dominion

Posted on November 26, 2018 by john | 40 views

Intro Every now and then you find a product that is a leap ahead of where you were. Such is the case for us with regards to our product of choice for serial consoles. The old For Bluecoat (Symantec) proxy … Continue reading →

Posted in Admin, Security | Tagged , , , | Leave a comment

Counting active leases on an old ISC DHCP server

Posted on November 16, 2018 by john | 68 views

Intro Checkpoint Gaia offers a DHCP service, but it ias based on a crude and old dhcp daemon implementation frmo ISC. Doesn’t give you much. Mostly just the file /var/lib/dhcpd/dhcpd.leases, which it constantly updates. A typical dhcp client entry looks … Continue reading →

Posted in Admin, Perl | Tagged | Leave a comment

Linux tip: how to enable remote syslog on SLES

Posted on July 27, 2018 by john | 74 views

Intro I write this knowing I still don’t know anything to speak of about syslog, but, sometimes you gotta act without knowing. I needed to send syslog to somewhere in a big hurry so I figured out the absolute minimum … Continue reading →

Posted in Admin, Linux, Network Technologies, SLES | Tagged , , | Leave a comment