SNMP v3 and Cacti
A quick synopsis on setting up a Cisco ASA and a Centos 6 or 7 system to use SNMP v3 to be monitored by Cacti Cisco ASA en conf t # create a snmp-server group (needed for SNMP v3) # … Continue reading →
Category Archives: Linux
crontab day of week vs day of month
You want to set up a crontab where something happens every weekday morning, i.e. 8 am every Monday, Tuesday, Wednesday, Thursday, and Friday in January from the 10th to the 30th. You set up your crontab with the following 0 … Continue reading →
How to mount raw images (.img) images on Linux
If you have a few .img files coming as disk images from devices like floppies, CDs, DVDs, SD cards, etc, you will realize that you cannot mount the in Linux, because they contain a file system that has to be … Continue reading →
Turn off wifi radio in Linux / Centos
I have a few boxes that have built in wifi and I dont need it turned on. So I turn it off using the following command nmcli radio wifi off To make sure the wifi radio stays turned off in … Continue reading →
Web Site Certificate/SSL Tests
I have found the following two sites helpful in finding issues with the configuration of SSL secured web sites https://ssltools.digicert.com/checker/ https://www.ssllabs.com/ssltest/analyze.html Test which ciphers (TLS, SSL, etc) are enabled nmap -sV –script ssl-enum-ciphers -p 443 www.yourdomain.com Ref: https://nmap.org/nsedoc/scripts/ssl-enum-ciphers.html
Continue reading →Edit Transport Maps On Postfix
If you need email delivered to a specific server for selected domains you do the following: As root, edit the /etc/postfix/main.cf. Find (or add) the line that starts with transport_maps= If it does not exist, add the line “transport_maps=hash:/etc/postfix/transport. If … Continue reading →
ssh fails to connect with debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
Running ssh across a vpn connection I started having my ssh sessions fail to connect. After starting ssh with the “-vvv” option, the session would timeout after getting a debug1: expecting SSH2_MSG_KEX_ECDH_REPLY After doing some research, I found other people … Continue reading →
3 command-line file conversion tools for Linux
Pandoc Everyone I know who works with markup languages says Pandoc is the go-to utility for converting between those languages. And for good reason: Pandoc not only does some pretty nifty conversions, it’s fast, too. Have a file formatted with … Continue reading →
Using UUID to Mount Disk
In linux, hard drive dev assignments can get changed between reboots – especially with external/removable drives. This means using /dev/sdX or /dev/hdX is not the best way to mount a drive that needs to be mounted every time at boot. … Continue reading →
Security Wipe Of Hard Drive Using Linux
first – determine the dev of the hard drive – as in /dev/sda /dev/sdb etc Then excute shred -vz -n 3 /dev/XXX where XXX is the identifier of the hard drive Increase 3 to a larger value for higher security … Continue reading →