How do I flush DNS?
July 1, 2008 – 5:35 am | 195 views
Most DNS clients cache the results of name resolution requests. This speeds up name resolution if multiple lookups are done to the same address, such as is common when browsing the web.
Sometimes a bad DNS entry will be cached and you will need to either flush the DNS cache to get rid of it, or wait up to 24 hours for it to be dropped from the cache automatically.
How to Flush DNS in Microsoft Windows
In Microsoft Windows, you can use the command ipconfig /flushdns to flush the DNS resolver cache:
C:\>ipconfig /flushdns Windows IP Configuration Successfully flushed the DNS Resolver Cache.
You can also use the command ipconfig /displaydns to view the DNS resolver cache.
Turning off DNS Caching under Microsoft Windows
If you experience frequent issues with DNS caching under Microsoft Windows, you can disable client-side DNS caching with either of these two commands:
- net stop dnscache
- sc servername stop dnscache
This will disable DNS caching until the next reboot. To make the change permanent, use the Service Controller tool or the Services tool to set the DNS Client service startup type to Disabled.
Tuning DNS Caching under Microsoft Windows
You can modify the behavior of the Microsoft Windows DNS caching algorithm by setting two registry entries in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters registry key.
The MaxCacheTtl represents the maximum time that the results of a DNS lookup will be cached. The default value is 86,400 seconds. If you set this value to 1, DNS entries will alt=”Flush DNS”>
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DNS and BIND
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DNS & BIND Cookbook
The DNS & BIND Cookbook presents solutions to the many problems faced by network administrators responsible for a name server. Following O’Reilly’s popular problem-and-solution cookbook format, this title is an indispensable companion to DNS & BIND, 4th Edition, the definitive guide to the critical task of name server administration. The cookbook contains dozens of code recipes showing solutions to everyday problems, ranging from simple questions, like, “How do I get BIND?” to more advanced topics like providing name service for IPv6 addresses. It’s full of BIND configuration files that you can adapt to your sites requirements.
With the wide range of recipes in this book, you’ll be able to
- Check whether a name is registered
- Register your domain name and name servers
- Create zone files for your domains
- Protect your name server from abuse
- Set up back-up mail servers and virtual email addresses
- Delegate subdomains and check delegation
- Use incremental transfer
- Secure zone transfers
- Restrict which queries a server will answer
- Upgrade to BIND 9 from earlier version
- Perform logging and troubleshooting
- Use IPv6
DNS on Windows Server 2003
While computers and other devices identify each other on networks or the Internet by using unique addresses made up of numbers, humans rely on the Domain Name System (DNS), the distributed database that allows us to identify machines by name. DNS does the work of translating domain names into numerical IP addresses, routing mail to its proper destination, and many other services, so that users require little or no knowledge of the system. If you’re a network or system administrator, however, configuring, implementing, and maintaining DNS zones can be a formidable challenge. And now, with Windows Server 2003, an understanding of the workings of DNS is even more critical.
DNS on Windows Server 20003 is a special Windows-oriented edition of the classic DNS and BIND, newly updated to document the many changes to DNS, large and small, found in Windows Server 2003. Veteran O’Reilly authors, Cricket Liu, Matt Larson, and Robbie Allen explain the whole system in terms of the new Windows Server 2003, from starting and stopping a DNS service to establishing an organization’s namespace in the global hierarchy.
Besides covering general issues like installing, setting up, and maintaining the server, DNS on Windows Server 2003 tackles the many issues specific to the new Windows environment, including the use of the dnscmd program to manage the Microsoft DNS Server from the command line and development using the WMI DNS provider to manage the name server programmatically. The book also documents new features of the Microsoft DNS Server in Windows Server 2003, including conditional forwarding and zone storage in Active Directory (AD) application partitions.
DNS on Windows Server 2003 provides grounding in:
- Security issues
- System tuning
- Caching
- Zone change notification
- Troubleshooting
- Planning for growth
If you’re a Windows administrator, DNS on Windows Server 2003 is the operations manual you need for working with DNS every day. If you’re a Windows user who simply wants to take the mystery out of the Internet, this book is a readable introduction to the Internet’s architecture and inner workings.