H5: Update titles

exercises/h5.md

@@ -63,7 +63,7 @@ About relevance of the `-D` parameter has been discussed, for instance, on [supe
 
 **Answer:**
 
-The firewall protection is done by using Linux kernel ip_table module(s). Firewall rules can be modified in User Space with the corresponding iptables command or with the simplified Python 3 based program/script 'Uncomplicated Firewall' (`ufw`). Other firewall solutions also exists on Linux, please see title 'Other firewall solutions' below. 
+The firewall protection is done by using Linux kernel ip_table module(s). Firewall rules can be modified in User Space with the corresponding iptables command or with the simplified Python 3 based program/script 'Uncomplicated Firewall' (`ufw`). Other firewall solutions also exists on Linux, please see ['Other firewall solutions'](https://github.com/Fincer/linux_server_setup/blob/master/exercises/h5.md#other-firewall-solutions) below. 
 
 We can check which loadable kernel modules have been enabled in Linux kernel with the kernel-related lsmod command.
 
@@ -81,7 +81,9 @@ x_tables               36864  14 ip6table_filter,xt_hl,xt_recent,ip_tables,xt_tc
 
 Source codes of these modules can be found on git.kernel.org: [ipv6 netfilter](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv6/netfilter), [ipv6 netfilter core](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv6/netfilter.c), [ipv4 netfilter](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/netfilter), [ipv4 netfilter core](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/netfilter.c)
 
-By default, Uncomplicated Firewall (`ufw`) is usually pre-installed on many Linux distributions, including Debian-based systems. Let's confirm that:
+### UFW configuration
+
+By default, python-based Uncomplicated Firewall (`ufw`) is usually pre-installed on many Linux distributions, including Debian-based systems. It's usually the default firewall front-end for `iptables` on Linux systems. Let's confirm that:
 
 ```
 phelenius@my-machine:~$ if [[ $(dpkg --get-selections |grep ufw | awk '{print $1}' | wc -l) -eq 0 ]]; then sudo apt-get update && sudo apt-get -y install ufw && echo "REPLY: UFW is installed now"; else echo "REPLY: UFW has already been installed"; fi