Category Archives: Admin

Postfix Operational tips

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

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

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

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?

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

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

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

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

The IT Detective Agency: the vanishing certificate error

Intro I was confronted with a web site certificate error. A user was reluctant – correctly – to proceed to an internal web site because he saw a message to the effect: I tried it myself with IE and got … Continue reading

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

The IT Detective agency: Some insights into 4096-bit SSL keys

Intro I was recently asked if a new certificate a web site is about to deploy would require any changes to our clients such as needing to import this certificate into their Java keystore. The details Well, I saved the … Continue reading

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