Update System_Configuration.md

Author: NextGenSec-Github

DFIR/Digital Forensics/Linux/System_Configuration.md

@@ -53,6 +53,27 @@ It serves as a local DNS (Domain Name System) resolver, mapping hostnames to IP
 
 **Blocking or redirecting:** Redirecting certain hostnames to alternative IP addresses, such as blocking access to certain websites by redirecting them to localhost.
 
+## DNS Resolution (/etc/resolv.conf)
+The `/etc/resolv.conf`is used to configure DNS (Domain Name System) resolver settings for the system, specifying which DNS servers to use and other related parameters. Here's a typical example of what you might find in an /etc/resolv.conf file:
+```bash
+# Generated by NetworkManager
+nameserver 192.168.1.1
+nameserver 8.8.8.8
+```
+The /etc/resolv.conf file is typically generated automatically by network configuration tools such as NetworkManager or DHCP (Dynamic Host Configuration Protocol) clients when the system obtains network settings from a DHCP server. However, you can also manually edit this file to configure DNS settings.
+
+### In addition to nameserver entries, the /etc/resolv.conf file may include other directives such as domain, search, options, and sortlist, which provide additional DNS configuration options:
+
+- **domain:** Specifies the default domain name used for unqualified hostnames.
+
+- **search:** Specifies a list of domains to append to unqualified hostnames during DNS resolution.
+
+- **options:** Specifies various DNS resolver options such as timeout values, DNS search order, and more.
+
+- **sortlist:** Specifies a list of IP address/netmask pairs to control the order of address resolution.
+
+
+
 
 ## ip addr show 
 The command "ip address show" (or its shorthand "ip a") is a powerful tool used in Linux systems to display information about network interfaces and their associated IP addresses. It provides detailed information about the networking configuration of the system.