DNS Time to live, aging and scavenging

[@BijouBakson]

I've learnt more from this playlist than anytime during my years of training. I remember we only brushed through this subject. Even though it's about 6 years, 99% is still relevant as I am testing it versus Windows Server 2019 Datacentre. So this is real gold. Thank you.

[@jadenstefan9231]

Sorry to be so off topic but does someone know a tool to get back into an instagram account? I somehow forgot the account password. I appreciate any help you can give me

[@legotrekker]

I've become a one-person IT team at my workplace because nobody else is available who is capable of fulfilling the task and i am auickly headed foward defacto network administrator assuming that I can learn these systems quickly and resolve the many problems we're having due to our operations manager having many positions (including network administrator) for which he is not trained or knowledgeable. These videos are a godsend and its shocking how much of this information has been totally unchanged in the last decade! Thank you so much. I'm considering learning from your A+ series and going for my certification now.

[@itfreetraining]

It sounds like you're stepping into a significant role, and it's great to hear that you're eager to learn and grow in your IT skills! It's impressive that you're taking on these responsibilities, and with your proactive approach, you're sure to make a positive impact on your workplace. If you have any questions or need guidance as you prepare for the A+ certification, feel free to reach out! Good luck on your certification journey!

[@MagnumOpus1122]

This is by far the best video series for DNS out there on Internet. Job Well Done ! Kudos

[@itfreetraining]

Thank you so much for your great feedback!

[@MagnumOpus1122]

You deserved it. Keep up the good work.

[@yekolotemari]

The DNS series is well done. In fact, all your playists are amazing. I am experienced in AD/Directories but your videos made a lot of concepts I took for granted clear.

[@itfreetraining]

Thanks for your kind words! We really appreciate it!

[@abdelalielghazrani5956]

you deserve million likes for your explanation. perfect

[@itfreetraining]

Thanks, glad we could help.

[@BijouBakson]

I keep coming back here for reference. This is totally better than most paying courses I've attended. Thank you so much.

[@itfreetraining]

Thanks for watching.

[@BijouBakson]

@@itfreetraining Ironically I am actually finishing the DNS playlist today, for the first time. The course is still very relevant, even 9 years later, which in computer years is almost a century. You're welcome.

[@charlest7396]

I go to college and am an inspiring IT professional and online student your videos are very informative and easy to understand I like the way you thoroughly explain everything. Thanks alot

[@itfreetraining]

+Charles Thomas You're very welcome. Best of luck in your IT career!

[@romulosanchez138]

Another Great video from Itfreetraining... thanks. I was looking at a MS book trying to understand the scavenging process but was going no where, watch the video and it is so clear now. Your videos are so professional and I just love the voice, calm and so nice to listen. Your videos set the standard so high, other companies making video training should help you making a profit by watching yours and learn something :-)

[@itfreetraining]

Thanks. It is great to hear that you like the videos. More videos on the way.

[@TheHeywoodkenobi]

When you were on NYDC1 under the Server Aging/Scavenging you said you were not going to select it but you hit ok instead of cancel. Pretty sure that selected it. Otherwise this is the best tutorial I've seen on setting this up the only thing missing is a section on how DHCP affects this process.

[@AlanChristensen]

An excellent video that clearly and concisely covers a tricky subject. Thank you!

[@itfreetraining]

Thank you, glad we were able to help. Regards, ITFreeTraining

[@liptongtr]

Great information, was just looking through this on our production environment when we ran into some DNS issues, explained the two things I was a little unsure about. Thanks!

[@ronadona]

Thanks Sir, this is really clear and helpful. I suggest you start making books with video tutorials for other things. Your level of professionalism shouldn't be limited to AD, you should do Exchange, SQL and any other content that System Administrators need. All MS students would appreciate such a thing and of course be happy to pay well for it. You're a free service but we're always happy to pay for premium services. and your service is much higher than being premium.

[@yalandolan3000]

Great video. Thanks! I think we all need to go back and do a bit of testing ourselves to go over these concepts. As you've said, there's a lot that's being covered here :)

[@itfreetraining]

Great idea! Thanks for the great feedback and for watching the video!

[@RajneeshGadge]

One of the best videos on this topic, very nicely explained. made me like and subscribe the channel. Keep up the good work. :)

[@othmanabukarma1086]

Best OF The Best Place To Learning IT

[@itfreetraining]

Thanks very much.

[@James-sc1lz]

Exceptional video. MS have made this really, really stupid and misleading. They always over complicate things and I have no idea why. This makes this video so essential.

[@guptaramkumar52]

Awesome, you always explain in details in very detail manner. Could please upload a video on difference between active directory 2012/2016/2019 and what all the new feature in these version AD.

[@santho131986]

excellent guys. Videos are most useful and making use of all you uploads.

[@itfreetraining]

+santhosh kumar viswanathan Thank you for the kind words and thanks for watching. We are happy you found our videos so useful.

[@georgizhilov2086]

Awesome video, clear explanations, greatings from Bulgaria ;)

[@itfreetraining]

Glad you enjoyed it!

[@VijayKumar-uc5bf]

Now I am able to understand the DNS Time to live, aging and scavenging. Thanks a Lot... :-)

[@itfreetraining]

You're most welcome! Thanks for watching ITFreeTraining!

[@abelbekele2607]

Thank you for these great videos.They're wonderful. I have discovered plenty of concepts discussed are exam objectives for the MCSA 70-411 exam. May I suggest you create a playlist named 70-411 as it may help aspiring Microsoft certified techs , myself included. Thanks again.

[@govind482]

Very advanced level explanation....Really very useful. Thanks Sir.

[@itfreetraining]

You're very welcome.

[@rebelrobot]

Brilliant video, thanks!

[@itfreetraining]

Thank you, we're glad our videos are helpful

[@DavidOkeyode]

Best explanation that I've ever heard on this!!!!!! Are you planning to release any new courses? I'll happily pay for them even though I'm a developing instructor myself.

[@itfreetraining]

+David Okeyode We are always working on releasing new videos. We offer our videos for free, however we are working on a donation link if you were still interested in assisting. Thanks for watching!

[@50PullUps]

Whoa, an actually helpful explanation! My cert guide devotes a page to this dense topic.

[@gamerluke7]

Thanks. You made it easy to understand this topic.

[@daar1497]

i have entries that the time stamps are months old and dont know why they haven't updated... others do update with no problem... scavenging is disabled now... when i enable scavenging... will all those entries with old time stamps be deleted?

[@asdfgghfd2041]

I still cannot comprehend some things. I do not have scavening enabled yet. But.. I assumed that no-refresh interval doesn't allow specific computer to update its timestamp for 7 days, but it allows to update its IP address. Today i've changed my computer IP address and the timestamp got updated after that change despite being 2 hours old. What did i miss ? Besides in the SOA tab of the zone there are setting like refresh interval (default 15 min), retry interval (default 10 min), Expires after ( default 1hr), TTL (default (1hr). Could you please explain it ?

[@itfreetraining]

Scavenging is the process of removing the DNS record from the database. Dynamic update it the process of allowing the IP address to be updated after the DNS record has been created. They are two different things. You can always dynamical change the IP Address assuming you DNS servers supports dynamic updates. Refresh interval is the SOA is how often a DNS server using that information will keep using it before it contacts an authority server to get a new version.

[@abdulqadir374]

What i dont understand her is that the aging time is 7days upto 14 days. That means within first 7 days client is not able to update timestamp until it ip address is changed but after 7 days till 14 days the client will keep on updating the timestamp every it restarts so what is the benefit here because replication will happen continuously after 7 days upto 14 days. Please clarify this.

[@lincolnjordaan3766]

You are the best!

[@itfreetraining]

Thanks for watching.

[@alexrebo7772]

great training material and explanation, thanks!

[@itfreetraining]

You're welcome!

[@bammbiniinuk]

Very good videos, Thanks!

[@itfreetraining]

Thanks, glad you enjoy our videos.

[@3eenab]

Excellent work, thanks again.

[@itfreetraining]

You're most welcome. Thanks for watching.

[@TheHeywoodkenobi]

I think you missed a setting maybe my attention was drawn elsewhere but I didn't see you enable automatic scavenging of stale records under the server's advanced properties tab.

[@itfreetraining]

Interesting point, thanks!

[@Dr.Schultz.]

Perfect explanation. Thank you!

[@itfreetraining]

You're welcome!

[@luekuch13]

Thank you for your excellent explanation of DNS TTL, aging and scavenging. But I still have some ambiguities: 1. When a client with dynamic DNS is in the "no-refresh-intervall" and his IP-address is changing, is the time-stamp going to be refreshed or not? 2. And when the time-stamp is going to be refresh, is the "no-refrsh-intervall" going to start from the beginning? 3. Does a resource record with the scavenging option disable also has a time-stamp? Thank you in advance!

[@govind482]

No Time-stamp will not be changed. Time stamp only change during refresh interval

[@govind482]

during refresh interval other information like dns record ip address will not be update

[@mk47508]

Perfect explanation, please come up with windows 2016/2019 trainings

[@itfreetraining]

Thanks!

[@bhakta_rg]

great explanation. thanks for the videos. had a few questions, why would the timestamp on the DNS record need to be updated by a client? every time a client/computer boots up, does it have to update the DNS record? im confused. And how would the DNS server know when to remove a DNS record if its no longer needed?(meaning a client is taken down/server retired,etc.)

[@itfreetraining]

If DNS is configured for scavenging it will automatically remove the DNS record if it is not updated. Consider that you have a laptop. The laptop is put on the network and is used on the network for a week. The user then takes the laptop off site for a month. Without scavenging, the DNS record will stay there and an administration may think the laptop is still on the network. It essentially just a way of getting rid of DNS record that are no longer required. It is however up to the client to notify the DNS server that it is on the network and update the time stamp.

[@bhakta_rg]

@@itfreetraining brilliant. thank you for the crisp and clear explanation. Much appreciated. God bless you guys! Just one follow up question on that. So when a new workstation gets plugged into a corporate network, is a DNS record for that automatically created? or the administrator needs to create one explicitly? meaning, are workstations any different than regular servers or tape libraries on a corporate network? thanks!

[@itfreetraining]

@@bhakta_rg If dynamic DNS is enabled and the workstation has permission it will be able to create the DNS record. In Windows, if you have secure updates enabled then the computer will need to part of the domain in order to create a DNS record. If you do not have secure updates on then essentially any device that uses DNS can potentially create it's own DNS record.

[@paelana]

Very informative; thank you!

[@itfreetraining]

Thank you.

[@hunjankuljit7]

Great Job !!

[@panflin88]

Great video, Thanks a lot for that. !!!

[@daleanbarnett5088]

Will you guys be releasing any videos regarding Microsoft Windows Server 2016?

[@itfreetraining]

We're always working on new videos!

[@pushparajgothandam8527]

Thanks for explaining how to remove unused DNS enrty in DNS server using Scavenging. But I just want know how we can remove unused computer objects in Active directory ? If DNS entry associated with computer object removed when scavenging happens?

[@itfreetraining]

If you remove the object in Active Directory it will not remove the DNS entry. They are independent of each other. If you have scavenging enabled, if the computer does not renew it's computer name in DNS scavenging given enough time will remove the record based on the settings configured. The same applies if the computer is not used for a long time. If this is the case, even though the entry of it still exists in Active Directory, the entry in DNS will be removed by Scavening. When the computer starts up again, the DNS entry will be created using dynamic update. If you are sure that you have an object in Active Directory that is not being used, you can delete it.

[@pushparajgothandam8527]

itfreetraining Thanks for explaining . I understand that We can delete unused computer objects manually and scavenging deletes the DNS entry when no dynamic update on it.

[@Yuki_Nagato]

really interesting and really good explained :)

[@itfreetraining]

+Yuki Nagato 長門 有希 Thanks! We're glad you found it interesting. :)

[@133major7]

what is refresh timer ? what is interval timer? what is ttl?

[@itfreetraining]

Refresh timer and no-refresh interval refers to DNS records that are added to a DNS server using dynamic update. The no-refresh interval prevents the DNS record from being updated in that time period. If the DNS record is in the refresh time period, it can be updated. The best way to understand this is to consider why they do it this way. When a client updates it DNS record using dynamic update, since the record has changed it needs to be replicated. If you have 100's of computers on a networks, that is 100's of computers that are updating their DNS records. For example, every time a computer starts it will dynamic update it DNS record. This is a waste of replication bandwidth keeping all DNS servers up to date. However, at some stage you will want to update the DNS record. So during the refresh timer period the DNS record can be updated. If the DNS record is not updated by the end of the refresh period it is removed. So consider they are both set to 7 days. Once a client registers using dynamic DNS, all updates will be ignored for the next 7 days. Between 7-14 days, if the client registers using dynamic DNS the record will be updated setting the time period back to zero. So back to 7 days of not being able to be updated. If no dynamic update is received between 7-14 days, the DNS record is removed. This reduces replication for each DNS record to once per week. Since once it is added or changed, it cannot be updated for 7 days. It also prevents DNS records staying on the DNS forever. If no update is received between 7-14 days the DNS record is removed. I am not sure what you mean by interval timer. It probably referring to the time period being set to 7 days. TTL. It is the time that the DNS record will remain in cache before it is removed. The DNS client will then have to perform another DNS querry to obtain the DNS record again. A lot of newer videos we are reducing the amount of topics covered in each videos. I think this is where people get confused when there are multiple topics covered in the same video even when they are related.

[@133major7]

i understanding now good explaining

[@itfreetraining]

Excellent! Glad we could help.

[@cannedtooth]

I'm not sure how itfreetraining dot com makes money out of this but they should get some money somehow so they can continue on making quality video IT tutorials. If they decide to sell training videos one day i'd be happy to purchase one if i'll need IT training. I can easily say that their video tutorials can be compared to CBT nuggets and train signal training videos. Keep on making good IT videos.

[@itfreetraining]

Thanks very much. We make money from the ads on the videos so you watching the videos is enough for us.

[@Clown90125]

+cannedtooth I thought exactly the same thing.

[@itfreetraining]

+Culpano As long as you the viewers keep watching our videos, we continue to make money. Thanks for watching!

[@TiagoBigodeTI]

Parabéns!

[@itfreetraining]

+Tiago Toledo Faria Thanks.

[@Nsadheo]

thank you

[@itfreetraining]

You're welcome!

[@manuloffice713]

2023 and this is really helpful

[@itfreetraining]

Thanks very much.

[@133major7]

i can`t understanding anything of this lecture

[@133major7]

your way of explaining is so hard ,delete these videos and try to upload another lectures with little easier of explaining this is so hard i repeat all your videos lots and lots of times but i don` understanding what you want to say Albert Einstein said " If you can't explain it simply, you don't understand it well enough."

[@itfreetraining]

Have you watched the first video on what is DNS? If you don't understand DNS to start with you will probably have difficulty with the videos. kzbin.info/www/bejne/jWGalat5h6qCisU The videos are designed for those who want to or are working in the IT field so tend to get a bit technical, but we do our best to make them simple to understand. What are you not understanding? What is in the video that is making it hard? I am happy to take feedback, but when we get close to 100% likes on every video we upload, the community clearly likes the videos. So I won't be deleting any. However will use feedback to make them better.

[@133major7]

ok i finish ccnp r&s , so i have technical knowledges

[@133major7]

ok look try to make your language little easily iam mohamed from Egypt my native language is Arabic not english like you so keep this thing in your mind when you are uploading new videos that they`re some peoples who need to see you can`t understanding your native english so easily , so tyr to make your speaking and your explaining little easily

[@itfreetraining]

Thanks for the suggestion!

[@baljindersingh-gq7sx]

good

[@itfreetraining]

Thanks

[@alihaleem2705]

great video again .. thanks alot

[@itfreetraining]

Thank you and you're welcome!