Being a distributed, hierarchical and global database for host information, the Domain Name System or DNS is one of the internet’s most fundamental building blocks. Acting like the internet’s phone book, it translates every domain name that humans find meaningful into number identifiers for the objective of addressing and located devices on worldwide networks. It goes without saying that productivity can be crippled by DNS issues. Not to mention the fact that your business’ profitability can be hampered. In other words, your DNS can be your friend or your foe. Problems with the DNS can stop you from accessing sites online. This can even happen during times when you most need to be online! If you are having trouble with your internet connection, you will need to check to see if the cause is the DNS. If you are into server issues, you might want to learn Java Script Server Technologies from scratch, and this course shows you how.
Basically, the DNS is fundamental in getting connected to the net. Every device that is able to connect to the internet whether it is a gaming console, a smart phone or a personal computer looks up each of the names you input into a global Domain Name System. The Internet address that results connects you to a server on the web, lets you send electronic mail or lets you use the World Wide Web. Trying to pass the Microsoft Querying Server Exam? Here is a course that helps you do just that.
One of any Windows network’s essential services, the DNS is essential as active directories are not going to be able to function without it. Other network functions also use DNS. This is why it is important to quickly trouble shoot any DNS issues that appears. Here is a course called SQL Server Essentials: What You Should Know about server essentials you might also be interested in.
No Registered Records
Efficient DNS appliances are important for constantly monitoring records of DNS within your area. These enable you to avoid these issues that tend to hamper productivity. One solution for this type of DNS error offer database management, a centralized domain, ease of integration, diagnostics, auditing, verification and data integrity that ought to fulfill the required DNS management where you are concerned.
A SNAME error that refers to domain names that don’t have corresponding IP addresses is one DNS error that is fairly common. Errors such as these could cause failures of lookups and, due to the server that does not exist, make it impossible for a user to access critical services online. By now you most likely understand that your PC connects to other networks using a specific ‘language’ or protocol to speak to other PC’s. There are communication rules called TCP/IP, which many network technicians use for internal communications between computers. Here is a comprehensive article called IfconfigDHCP Command Line Network Settings to understand this application better.
Hard to Access FTP or SAP services
Many ERP systems do lookups of DNS in reverse domains in order to verify the legitimacy of original IP addresses. That is, ERP systems look up records mapping an IP address to a domain name. If DNS administrators incorrectly configure the reverse records, a user won’t be able to access FTP or SAP services.
Unreachable DNS Server
Often, a DNS server can become hard to reach due to practices involving firewalls, mistakes or crashes in the machine or due to service halts of DNS. This causes a server that fails to respond which in turn results in increased times for lookup and decreased efficiency of the system. Users might not be able to access their email accounts, the web or may even stop getting their DNS queries answered. If the DNS client is able to ping its server computer, verify that the server of the DNS has started and is able to respond and listen to requests of the client. To do this, you can use the command nslookup to test whether DNS clients can be accommodated by the server.
Faulty DNS Sub-Domain Delegation
A faulty DNS sub-domain delegation is one of the most common DNS issues. This can result in failure of registering DNS services in Active Directory or in slow lookups. As a result, users might not be able to log on to their computers or access vital data. This can also cause a delay in response times.
Issues with Your Proxy Servers
This issue comes up especially if you subscribe to something that runs on a proxy server, like AOL for instance. A proxy server sits between the actual internet and you. These are used to prevent access to certain web services and websites as well as to locally cache or store content that does not change very frequently. Many times, a proxy server operates without you realizing that they are even there.
Viruses That Look Like DNS Issues
At times, when you would make attempts to visit certain sites on the web, you may instead get redirected to malicious sites that seemingly come out of nowhere. You may initially suspect an attack of DNS poisoning but if you notice that just one computer is affected, then there is a virus. The issue could be that the virus integrates itself into the stack of TCP/IP and intercepts every request for name resolution. This could appear to be a DNS issue initially, but really, the thing to blame is the virus.
Round Robin DNS
At times, High demand web servers hosted by organizations make attempts to get the workload distributed across identical multiple servers on the Web through using a technique of load balancing called Round Robin DNS. This technique has a few issues, one being that the DNS servers have no way of knowing when there has been a failure in one of the servers. Because of this, all traffic inbound is directed to all the servers in a round robin style, even with one offline server. You get problems in the load balance resource and issues in intermittent connectivity when this happens.
Names are Not Resolved Correctly by the DNS Server
One issue that sometimes comes up is that incorrect data is provided by your DNS server for successfully answered queries. There are a few likely causes for this. One cause is that errors were made when static records of resource where added manually or modified in the zones. Sometimes, resource records were not updated dynamically in zones. Another reason could be that stale records of a resource in the database of your DNS server has been removed when no longer needed, not updated or were left from cached lookups.
Another issue is when a DNS server has gotten configured for disabling the uses of the reverse lookup zones that it automatically created. When this happens, you will need to verify that the reverse lookup zones automatically created have been created specifically for the server or that the chances in advanced configuration have not been made previously to server. In default mode, a DNS server creates standard lookup reverse zones automatically based on the recommendations of Request for Comments (RFC). Sometimes, the zones are not created when zone creation has been disabled as it involves manual advanced configurations of server registries by users.
Reverse Lookup is Not Enabled
At times, you come across DNS issues when reverse lookup zones are not enabled. A reverse lookup zone makes sure that your device’s name says that it is using the same as the name picked up by the DNS. You will need to enable reverse lookup zones on typical networks for things to run smoothly. To do this, check the domain controller in your Active Directory, since this is where you DNS server is. Double click on Administrative Tools after opening the control panel. Next, find where it says DNS and double click this. Click the name of the server and right click the Lookup Reverse Zones before clicking New Zone. You can now complete the process by following the zone configurations.
Network Failures can Cause DNS Issues
Failures of the network can affect your DNS server. When this happens, you will need to verify if the computer of the server has a valid network connection that is functioning okay. First, check the related hardware of the client including network adapters and cables. See if these are properly working. If everything seems to be functioning in the right way, use the ping command to see if network connectivity exists. The ping command helps you contact routers or other computers like a default gateway that are available and used on the same network as the DNS servers affected.
Users are Unable to Resolve Existing Names on a DNS Server Configured Correctly
When a name cannot be resolved by a user and yet the DNS server is configured in the right way, the first thing you need to do is to confirm that the name was not erroneously entered. Confirm the exact character site that the user entered when the original query of DNS was made. In addition, if the initial query used a name that was not the Fully Qualified Domain Name (FQDN), try using the FQDN in the client application instead and repeat the inquiry. Include the period at the name end to indicate that the entered name is exactly the FQDN. If the query with FQDN succeeds and in the response returns the right data, the most likely root of the issue is a misconfigured suffix in the domain search list that is utilized in the resolver settings of the client.
DNS Issues Due to Inconsistent Data
For integrated zones in the Active Directory, it is a possibility that the records affected for the queries have gone through updates in the Active Directory but have not been replicated in all the servers in the DNS that load the zone. All DNS servers by default that load Active Directory zones poll this at set intervals, usually every fifteen minutes. This also does zone updates for any of the zone’s incremental changes. Many times, the update of DNS takes not more than half an hour or less to replicate all the servers of the DNS used in the domain environment of an Active Directory that uses reliable high speed links and default replication settings.
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