Dynamic Host Configuration Protocol or DHCP, is used to assign IP addresses to devices. There are a couple different IP addresses you can use; static and dynamic. Once your devices are assigned addresses, they will eventually be able to connect to the internet!
Yes, you do if you want any sort of communication with the outside world! DHCP is provided by your home router, ISP, or a dedicated server. In addition, professional organizations will usually virtualize their DHCP and DNS servers rather than using physical hardware for those services.
On home networks you don’t usually have to do much to allow DHCP to run. You can verify that your network interfaces are set to receive IP addresses automatically though (this means you are selecting DHCP). You can also see your DNS address in the same area which we will over later. DNS and DHCP go hand-in-hand for the most part; they both relate to IP addressing and they are often confused with one another.
Are DNS/DHCP services or protocols?
Well, they are both services and protocols. They both involve IP addressing but their functions are quite different. The DNS stores a records of IP addresses to eliminate the need for remembering all of the IP addresses of websites.
The DNS cache provides a list of recent visited domains and their associated IP addresses. The purpose of the cache is to provide fast retrieval for quicker browsing sessions to those addresses. You can clear your cache in Windows cmd prompt by typing “ipconfig /flushdns.”
DNS / DHCP Comparison
|Runs on UDP/TCP port 53||Runs on UDP port 67/68 (server/client)|
|Resolves IP addresses into domain names making it possible to input web addresses ie. https://malwarebytes.com, into search bar and take you to that site||Assigns IP addresses to hosts by using static or dynamic IP addresses|
|There are several types of DNS servers, here are two examples:|
ResolverTranslates domain names into IP addresses
Root ServerAre responsible for providing overall DNS functionality across the entire internet. There are a small number of them
|Static IPDoesn’t change, usually used by servers or assigned by your ISP. Can be easy to memorize IP’s of your devices|
Dynamic IPAddresses are assigned by the DHCP server which may change. Most devices are configured with dynamic IP’s
Here you can see the DHCP and DNS services in “Services” Windows 10.
In Linux you can start, stop, and restart the DNS service with the “service bind9 start” command (or stop/restart). You can also view your DNS IP address with the “cat /etc/resolv.conf” command.
Network troubleshooting is very common especially for home users who don’t want to pay for a technician to come out to their residence. Understanding the basics of DHCP/DNS will allow you to save money by troubleshooting your home network personally. You must access the DNS/DHCP settings to become familiar with the interface…
How can I view my DNS and DHCP settings for my network adaptors in Windows?
There are two ways to do this; through command prompt (cmd) or through the network settings that are displayed with a graphical interface. You can access the network status screen from “Settings” and selecting “Network and Internet,” you are presented with this screen.
- Network status and select “Change adapter options”
- Right-click->properties or double click the adapter you want to edit
- You are presented with this window. Here you can see a summary of this adapter’s status. Next, select Details…
- Here we see if DHCP is enabled (it should be) and see our valid IP addressing.
- Now if we want to change the IP configuration we can go to Properties instead of details. Now double click the Internet Protocol Version 4 (TCP/IPv4) selection
- Here are the default values for this window. If your router etc. has DHCP and DNS then leave these radio buttons on the auto selections. If you are troubleshooting or want to get specific with your addressing you can change the IPv4. Now if you want to use a reliable DNS then you can use Google’s public DNS servers 22.214.171.124 or 126.96.36.199.
Alternatively, you can set the DNS server addresses for a third-party DNS tool like OpenDNS. We will get into DNS in a little bit but just know this is how you access your IP addressing configuration for your adapters.
- Now we can verify again that DCHP is enabled by clicking Advanced
You may be asking yourself what DNS is….
What’s DNS and is it essential?
The Domain Name Service (DNS) protocol matches IP addresses with domain names. For instance, when you search for a website in your browser’s search bar or type in a website URL and hit enter, the browser will return results.
Without DNS you could still access websites but you would have to put the IP address in the search bar. Example, “https://188.8.131.525” This would just make browsing more complicated having to add that extra step.
These results were found because the name server or DNS protocol was successful in resolving that domain’s IP address from a known domain list. The DNS information is retrieved from a DNS record in a database that stores known host names and their matching IP’s.
With that being said, you absolutely need DNS! DNS helps us all be as productive and time-saving as possible when conducting activities online. If there were no DNS, we would have to memorize or index all of the IP addresses for each and every domain we wished to connect with!
How can I troubleshoot DNS/DHCP networking issues?
There are several things we must do to troubleshoot networking issues. It is important to use a methodical approach to troubleshooting steps. You must go in order starting with the least intrusive step first.
By this I mean performing the step that requires the simplest action. If the problem persists then move up to the next step. The purpose is to avoid upsetting settings and configurations that are meant to stay the way they are during your troubleshooting. You don’t want to break something while you’re trying to fix something else.
- Identify Issue
Figure out what is the exact issue you are experiencing. Once that has been established, then understand what protocols, services, and equipment that could possibly influence that issue. If the issue is NOT persistent on another device connected to your network then it more than likely is a host based issue not a LAN/router issue
- Try these steps
Try pinging a host or router in your LAN? Can you ping a public IP address? (see screenshot below) If you can ping your router (192.168.50.1) then you know you are able to communicate with your internal network.
If you can ping a public IP in this case it’s Google’s public DNS server (184.108.40.206/220.127.116.11), then it may be a browser or firewall issue.
- Ensure your network interfaces are up and have valid IP assignments by running ipconfig or ipconfig /all
If you need help with ipconfig commands/options then you can type “ipconfig -h”; this brings up a list of options you can use along with ipconfig and their uses.
- Disable/enable network adapters
Right-click the affected adapter and click disable, wait 5 minutes, and hit enable; see if the issue persists.
- Unplug the network cable attached to device (if applicable)
After unplugging, wait 30 seconds and plug back in; see if the issue persists.
- Reboot device and see if issue persists
Oftentimes your device just needs to reboot in order to kick the funk out of the network settings or something. In my personal experience, it’s been a machine reboot that fixed the networking issue (no internet) pretty much after logging in post-reboot.
- Reboot router
Do this if the issue is persistent across all connected devices. Home routers can function fine with an uptime of a few weeks. It is recommended that they be rebooted a couple times a month just to keep them running fine.
In addition, keeping the router’s firmware updated is extremely important in order to keep the bad guys out. Malware can easily get into a router whose firmware is outdated.
- Perform network reset
This can be done by typing in the windows search box (lower Left-Hand side of screen), and typing in network reset. You will see the selection on the left side of the screen. Performing a network reset takes a little time so I wouldn’t recommend doing this unless you have ample time.
In summary, DHCP and DNS are both very important for internet browsing, IP configurations, and overall communication over the network. Knowing how to troubleshoot your home network will save you money, teach you a valuable skill, and enable you to learn more about your systems.
I hope you enjoyed this article and learned something that you can use!