After writing my last post on my IPv6 woes with my Pixel 3, some readers asked how I’m handling IPv6 on my router lately. I wrote about this previously when Spectrum was Time Warner Cable and I was using Mikrotik network devices. There is a good post from 2015 on the blog and it still works today: Time Warner Road Runner, Linux, and large IPv6 subnets I am still using that same setup today, but some readers found it difficult to find the post since Time Warner Cable has renamed to Spectrum.

We have two Google Pixel phones in our house: a Pixel 2 and a Pixel 3. Both of them drop off our home wireless network regularly. It causes lots of problems with various applications on the phones, especially casting video via Chromecast. At the time when I first noticed the drops, I was using a pair of wireless access points (APs) from Engenius: EAP600 EAP1200H Also, here’s what I knew at the time:

Managing iptables gets a lot easier with firewalld. You can manage rules for the IPv4 and IPv6 stacks using the same commands and it provides fine-grained controls for various “zones” of network sources and destinations. Quick example Here’s an example of allowing an arbitrary port (for netdata) through the firewall with iptables and firewalld on Fedora:

iptables iptables -A INPUT -j ACCEPT -p tcp –dport 19999 ip6tables -A INPUT -j ACCEPT -p tcp –dport 19999 service iptables save service ip6tables save ## firewalld firewall-cmd –add-port=19999/tcp –permanent In this example, firewall-cmd allows us to allow a TCP port through the firewall with a much simpler interface and the change is made permanent with the –permanent argument.

After a recent OpenStack-Ansible (OSA) deployment on CentOS, I found that keepalived was not starting properly at boot time: Keepalived_vrrp[801]: Cant find interface br-mgmt for vrrp_instance internal !!! Keepalived_vrrp[801]: Truncating auth_pass to 8 characters Keepalived_vrrp[801]: VRRP is trying to assign ip address 172.29.236.¹¹⁄₃₂ to unknown br-mgmt interface !!! go out and fix your conf !!! Keepalived_vrrp[801]: Cant find interface br-mgmt for vrrp_instance external !!! Keepalived_vrrp[801]: Truncating auth_pass to 8 characters Keepalived_vrrp[801]: VRRP is trying to assign ip address 192.

Although OpenStack-Ansible doesn’t fully support CentOS 7 yet, the support is almost ready. I have a four node Ocata cloud deployed on CentOS 7, but I decided to change things around a bit and use systemd-networkd instead of NetworkManager or the old rc scripts. This post will explain how to configure the network for an OpenStack-Ansible cloud on CentOS 7 with systemd-networkd. Each one of my OpenStack hosts has four network interfaces and each one has a specific task: