-
Recent Posts
- Practical Zabbix examples
- The IT Detective Agency: large packets dropped by firewall, but logs show OK
- Linux shell script to cut a packet trace every 10 minutes on Checkpoint firewall
- What is BGP hijacking?
- Trying to upgrade WordPress brings a thicket of problems
- Examining certificates over explicit proxy with openssl
- 3d printing a part for my deck
- Quick Tip: Powershell command to unblock a firewall port when running Windows Defender
- What’s Next In 3D Printing?
- Network utilities for Windows
- Monitoring by Zabbix: a working document
- Consumer tech: Samsung touchscreen not responsive
- Getting GNU screen to work on Windows 10 for a productive terminal multiplex environment
- Azure Cloud: can you swap public IP addresses on two VMs?
- The IT Detective Agency: the case of the Is it the firewall? or routing? or switch? or layer 2?
- The IT Detective Agency: WebEx and the case of the mysterious reset
- What I’m Working on Now: building my own 3D printer
- The IT Detective Agency: the case of Failed to convert character
- How to POST with curl
- No Internet, secure WiFi status message in Windows 10
-
Recent Comments
- Duncan Lake on Raspberry Pi photo frame using your pictures on your Google Drive
- Danal Estes on Bridging with the Raspberry Pi
- Luisa on Amazon Fire Stick/Sony BRAVIA TV compatibility problem – one solution
- Eric on Bridging with the Raspberry Pi
- Ryan Porter on Amazon Fire Stick/Sony BRAVIA TV compatibility problem – one solution
Archives
Categories
- Admin
- Ajax
- Apache
- CentOS
- Consumer Interest
- Consumer Tech
- Digital Currency
- DNS
- Exchange Online
- Firewall
- First Robotics
- flot
- Home Computing
- Hosting Service
- Image Manipulation
- Internet Mail
- IT Operational Excellence
- JavaScript
- jquery
- Linux
- Network Technologies
- ntp
- Perl
- Popular Science
- Proxy
- Python
- Raspberry Pi
- Scams
- Security
- SLES
- Spam
- TCP/IP
- Uncategorized
- Web Site Technologies
Meta
Category Archives: Security
Fail2ban fails to work, I built my own
Intro I’ve sung the praises of fail2ban as a modern way to shutdown those annoying probes of your cloud server. I recently got to work with a Redhat v 7.4 system, so much newer than my old CentOS 6 server. … Continue reading
Verifying a pkcs12 file with openssl
Intro The easy way How to examine a pkcs12 (pfx) file $ openssl pkcs12 ‐info ‐in file_name.pfx It will prompt you for the password a total of three times! The hard way I went through this whole exercise because I … Continue reading
Google Authenticator – not tough to self-host
Intro I wanted to learn a bit more about digital currencies. I’ll certainly be posting about them in the future. The best way to get some is to open an account with coinbase. But for security reasons – and I … Continue reading
Posted in Security, Web Site Technologies
Tagged 2FA, coinbase, gauth, Google Authenticator
Leave a comment
The latest on handling of SHA-1 certificates by the major browsers
Intro A certain organization is still using SHA-1 certificates internally, in spite of years of warnings, as I write this in February, 2017. But in the security world lack of action = eventual weakness. Ignorance is not bliss and putting … Continue reading
The IT Detective agency: the case of the incompatible sftp client
Intro I was asked for assistance with this sftp problem: $ sftp <user@host> DH_GEX group out of range: 1536 !< 1024 !< 8192 Couldn’t read packet: Connection reset by peerDH_GEX group out of range: 1536 !< 1024 !< 8192 Couldn’t … Continue reading
drjohnstechtalk now uses HTTP Strict Transport Security, HSTS
Intro I was reading about a kind of amazingly thorough exploit which could be done using a Raspberry Pi zero. Physical access is required, but the scope of what this guy has figured out and put together is really amazing. … Continue reading
Roll your own dynamic DNS update service
Intro I know my old Cisco router only has built-in support for two dynamic DNS services, dyndns.org and TZO.com. Nowadays you have to pay for those, if even they work (the web site domain names seem to have changed, but … Continue reading
Posted in CentOS, DNS, Linux, Network Technologies, Raspberry Pi, Security, Web Site Technologies
Tagged crontab, nsupdate, PHP, sudo
Leave a comment
Internet Explorer can’t access https page – maybe a client CERT is needed?
Intro I don’t see such issues often, but today two came to my attention. Both are quasi-government sites. Here’s an example of what you see when testing with your browser if it’s Internet Explorer: The details Just for the fun … Continue reading
IP address wall of shame
Intro It can be very time-consuming to report bad actors on the Internet. The results are unpredictable and I suppose in some cases the situation could be worsened. Out of general frustration, I’ve decided to publicly list the worst offenders. … Continue reading
Idea for free web server certificates: Let’s Encrypt
Intro I’ve written various articles about SSL. I just came across a way to get your certificates for free, letsencrypt.org. But their thing is to automate certificate management. I think you have to set up the whole automated certificate management … Continue reading
Posted in Admin, Apache, CentOS, Network Technologies, Security, Web Site Technologies
Tagged ACME, acme.sh, CERTbot, Let's Encrypt
Leave a comment