I started studying with RHEL 6 in April and switched over to 7 – As a result, I spent a lot of time honing iptables skills only to have firewalld take over (similar to sysvinit and systemd). I honestly prefer iptables as I am much more comfortable with it on the fly and the exam requirement states that you can still use iptables to fulfill any firewall requirements. Therefore, I think it might be helpful to some to show how to disable firewalld in favor of iptables. > systemctl disable firewalld > systemctl stop firewalld > yum -y install iptables-services Read more ». The iptables and firewalld services use the iptables userland component that talks to the netfilter kernel component.

The iptables and firewalld services are mutually exclusive, they can’t run at the same time. The iptables service is a pseudo service: it relies on the /etc/sysconfig/iptables file to set up the firewall configuration but doesn’t run permanently. To remove the iptables service, you can use the instructions given for disabling the firewalld service () and apply opposite commands (enable -> disable, disable -> enable, start -> stop, stop -> start). Personally i think firewalld is overally complicated for most server environments, it is probably more useful for graphical users.

Setting up a chain for a device (or assigning a zone to an interface in firewalld) is fairly simple in iptables directly, most servers have a single interface(or bonded single) so really the usercase is small. The addition of rich rules appears more complex then one directly in iptables. C program to implement dictionary using hashing function in java software. Not really sure what other Administrators do but I always insert iptables and save, this does not require a reload of iptables like they make you think is an advantage with firewalld Read more ». I am trying to use a spare router as a gateway for the internal zone.No internet access just to create an intranet of all my servers so as to practice then port forwarding between the internal zone and the public zone.Would you please post a link on how to do that. Also for some unexplained reason firewalld keeps assigning all my interfaces to the default zone.I assign them to other zones (–remove-interface and then –add-interface permanent etc and –reload)and although it is ok after a reboot they are all again stacked together in the default zone.I am furious beyond words.:) Read more ».

HAProxy is one of the most popular options for load balancing software, and this tutorial will demonstrate how to install and configure it on a server running CentOS 7. Install HAProxy. HAProxy is available on the CentOS repository, but it might not be carrying the latest release.