Tech notes

I have been experimenting with ZeroTier and wanted to share how I was able to setup site-to-site connectivity between a home network and AWS to avoid installing the ZT app on every system in my network. It is easier than you might think. This is a quick how-to on setting up site-to-site connectivity from a […]

I have put off learning how test-kitchen works with salt formulas for awhile. Mainly due to the multi-step setup process that can be slightly confusing if you are not accustomed to working with developer tools day to day. It became clear though that learning this workflow would be really beneficial for developing salt-formulas and other […]

PF_RING is software that installs a network socket allowing for “High-speed packet capture, filtering and analysis” https://www.ntop.org/products/packet-capture/pf_ring/. It is useful in applications where capturing a lot of network traffic is a requirement such as Snort or BRO IPS/IDS deployments. When possible, I use salt to manage pf_ring deployments but manual steps are condensed from the […]

At some point while working on a Salt formula to deploy pfring, I got to a point where I wanted to set promiscuous mode on an interface automatically. I wasn’t exactly sure how to go about it on RHEL/CentOS 7. So many things have changed so I set out to do a quick google search. […]

Rsync is an awesome tool that I have used extensively. However, I think it is time to explore other tools that can replace some of what rsync has been doing for so many years. I’m not saying that you should never use rsysnc. What I am saying is there are other options and in some […]

Subscription Management using subscription-manager Register a System subscription-manager register --username <username> --password <password> --auto-attach Disable managed yum repositories subscription-manager config –rhsm.manage_repos=0 Enable a specific channel subscription-manager repos –enable rhel-6-server-optional-rpms Sync RHN Profile rhn-profile-sync From https://access.redhat.com/solutions/253273

Accommodate growth of a VM by expanding an LVM partition At some point, a “physical volume” may have to be enlarged to accommodate growth on a VM. This is how you grow the filesystem of an existing VMDK without adding an additional disk to your VM. Enlarging a VMDK login to VMware Find the VM […]

This is not meant as a full primer for firewalld. It is just meant to document changing the default zone. If you are looking for a more in-depth exposure to firewalld try https://www.hogarthuk.com/?q=node/9 Check available zones firewall-cmd --get-zones Check active zone firewall-cmd --get-active-zones Get current zone of interface (assumes it is in the public zone) […]

Sorting /etc/passwd and /etc/shadow files Sorting /etc/passwd and /etc/shadow files [root@server~]# cd /root/ [root@server~]# touch passwd.sorted shadow.sorted [root@server~]# chmod 644 passwd.sorted [root@server~]# chmod 600 shadow.sorted [root@server~]# sort -t: -n -k3,3 /etc/passwd >passwd.sorted [root@server~]# gawk -F: ‘{system(“grep \”^” $1 “:\” /etc/shadow”)}’ passwd.sorted >shadow.sorted [root@server~]# wc /etc/shadow shadow.sorted 211 211 10985 /etc/shadow 211 211 10985 shadow.sorted 422 […]

This is post 4 of 4 in the series “Setup internal yum repositories for CentOS and RedHat Servers” Setup internal yum repositories for CentOS and RedHat Servers Part 1 Setup internal yum repositories for CentOS and RedHat Servers Part 2 Setup internal yum repositories for CentOS and RedHat Servers Part 3 Setup internal yum repositories […]