How To Get A Reverse DNS Lookup On The Command Line

Author: , September 1st, 2021

There are three commands in Linux to easily get a reverse DNS lookup with: dig, host and nslookup. Here are examples of each: shell> dig -x +short

shell> dig -x

shell> host

shell> nslookup

How To Fix DNS Lookup Issues on Macos Mojave 10.14.6

Author: , July 22nd, 2020

dscacheutil -flushcache System Preferences -> Network -> Advanced -> DNS -> Add, and at the top. If they are already there, CHANGE THE ORDER!

How To Fix Safari Using https instead of http

Author: , September 30th, 2016

For the Mac, you need to do three things in a row: 1. Quit Safari 2. Delete ~/Library/Cookies/HSTS.plist 3. Reboot

How To Enable DNS Hostnames for AWS VPC

Author: , August 8th, 2016

When you launch an instance into a VPC, AWS provides the instance with a public DNS hostname only if DNS hostnames are enabled for the VPC. By default, DNS hostnames are enabled only for default VPCs and VPCs that you create using the VPC wizard in the VPC console. If you enable DNS hostnames and […]

How To Get A Full DNS Zone Transfer

Author: , November 29th, 2010

To see all the records in a domain, use the ANY keyword with the dig command: dig @your.dns.server. ANY Commands for full DNS zone transfer of a domain: nslookup -query=axfr domain server dig -t axfr domain @server host -t axfr domain server

DNS Cache Poisoning

Author: , May 3rd, 2010

Ran into an odd problem this morning on my Verio server. Was unable to get DNS resolution on either or I was able to get DNS resolution on both my home systems and the ICI servers. That meant that the issue was specific to Verio. I called them. I was disconnected before i […]

How to Troubleshoot SSH on MacOSX

Author: , May 1st, 2010

I had some odd issues with slow login via ssh to my host. I looked in, but was not able to find anything relevant. So here is what I did: 1. System Preferences -> Sharing, Unchecked “Remote Login” 2. In Terminal, as root, ran /usr/sbin/sshd -ddd -e (3 d’s for debug level 3, -e […]

Busy, Busy

Author: , March 11th, 2010

Getting a lot done, just very busy today. Trying to keep everyone happy. I still have a slew of existing clients that require attention. Must finish the Dora domain registration cleanup today – it has been dragging for months. Finally got registry key info from them. Had to also clean up another client’s domain info. […]