.Net 3.5 Installation Error. Source File not found

While installing .Net 3.5 from Server manager we might end up with below error -

Quick Fix - 
1. Mount Current Operating System ISO on the VM.
2. Navigate to sxs folder under Sources\sxs. Once done, copy the path.

 

3. Proceed with installing .Net 3.5 again from Server manager.

4. Before clicking on Install, we need to Specify an alternate source path. This is because earlier while installing .Net, source files were not found.

5. Click on alternate source path & paste the path noted in Step 2. Once done click OK and Proceed with Installing.

Installation in Progress & it would be completed successfully this time.

Finish..

Logical Ports in Windows

1. Ports are logical connections which help in identifying which service or program on a server would be used.

2. Ports are always associated with an IP address.

For Ex - Let's consider we open google by typing www.google.com in the URL of a browser. Below are the things happens in the background - 

Name Resolution using DNS - This is to make sure FQDN's are converted into IP address which can then be processed by the computers.

Once name resolution is done, Port 80 for http or Port 443 for https will be appended with the URL IP.

Lets consider  www.google.com resolve to 142.250.194.228 & https is used in the URL, hence we will get something like - 142.250.194.228 : 443

Now here, IP address (142.250.194.228) would be helping in identifying the location/ country where the server is hosted. Once the server is located, then port number (443) would be used to determine https service from the server would be used.

3. There are three types/categories of Ports-

Well Known Ports  : Range [0-1023] - Mostly used by well known global services such as FTP,DNS,DHCP, HTTP, HTTPs and many more.

User or Registered Ports - [1024 - 49151] Companies/developer can use this to register their product / service. 

Empheral Ports - Range [49152 - 65535 ] These are used for creating outgoing connections from the server. These are assigned by the Operating system dynamically. 

Below are some common ports used day to day -

Finish..

Reliability Monitor

 A very simple tool that can be used to monitor System ( Software and hardware ) issues that occurred during a time interval.
It assigns a number/rating called "Stability Index" that shows server reliability.

Practical Usage - 

I used this tool a lot during troubleshooting Windows Servers OS. Assume there is an issue reported on xx day, so normally an admin will go to Event viewer to check all the logs during the time issue was reported to find the root cause, but we can make use of Reliability monitor as well to quickly have a glance on what happened prior or on the day issue was reported. This sometimes do save lots of time.

Using Reliability Monitor
Click Windows Icon --> Search with something like "Reliability" --> Click on View Reliability history

We will see something like below. Simply click on the date & view information.

Ex- On 28th Dec 2022, we can easily see there is a critical alert which states windows was not properly shutdown & along with that an informational event which states an application named "putty " was removed from the system.

We can then click on Technical detail to get some more information on the event / alert.

Finish..

Setting up Conditional Forwarders ?

 LAB Setup - I have two domain controllers as below -

DC2 holding Standard zone named "Testzone.com". It further have few Host A records such as VM1,VM2 and VM3.

DC4

Requirement is to setup a Standard Conditional forwarder for "Testzone.com" on DC4. This is to make sure who so ever is referring DC4 as it's Preferred or Alternate DNS should be able to resolve all the queries for Testzone.com.

Steps

1. We will navigate to DNS console on DC4 ( Can either login to DC4 and open DNS or directly connect from DC2 to DC4 DNS Console by going to DNS --> Right Click & Connect to DNS Server --> Type DC4 --> Ok

2. Right Click on Conditional Forwarders & Click New Conditional Forwarders.

3. We need to provide Zone name for which we are creating the conditional forwarder along with the Master DNS server IP which is holding that zone.

In this case, Zone is "Testzone.com" & Server holding that zone is "DC2".

Note - Since it's need to be a Standard Conditional forwarder hence, no need to check mark "Store this conditional forwarder in AD".

Testing name resolution from DC4, we will use below syntax -

Nslookup  query  DC4"

Finish..

Difference - DNS Conditional Forwarders & Forwarders ?

Both serve same purpose which is to forward a name resolution request but they are different in the way they operate.

Lost and Found in Active Directory ?

To understand Lost and Found concept, consider below example from my test lab.

I have two Domain Controllers (DC2 & DC3) in two different sites. Dc2  in a site named "Delhi" and Dc3 in "Pune" site. Replication schedule between both the sites are configured as 15 mins.

Note down below operations -

1. Now I have an admin who logs in to DC2 and move a user named "Abhishek Bansal" from Users container to an OU named "TestOU".  Since it's a change so it will be replicated to other DC's in the environment. As per schedule set it will be replicated to Dc3 in/after 15 mins.

2. Before change done in step1 would have been replicated to Dc3, some other admin logs into Dc3 domain controller & deleted "TestOU", meaning at step1 there is a change of moving an object to TestOU and at step2 someone deleted that OU before that change would have been replicated.

So the result of these operations will push user "Abhishek Bansal" into a special container called "Lost and Found".

So to sum-up, We have different kind of conflicts in Active Directory replication. One such type/kind of conflicts is Lost and found. It occurs when one update is putting an object in a container & before this update would have been replicated to other DC's  , there is one more update from a different DC which is deleting that container, as a result the objects that are moved in update 1 would be moved to a special container called "Lost and found". 

To view lost and found container under dsa.msc, you need to enable Advanced features by simply navigating to :  View --> Advanced features