DNS - Nameserver / Host Record Propagation Delays

There are a few reasons why you may not see changes you make to your DNS right away.  These processes are sometimes generally referred to as propagation, but these are the specific reasons.

1.  TTL (Time To Live)

TTL stands for Time to Live and is counted in seconds.  It is set by an authoritative name server which tells non-authoritative servers how long to cache records.  Our DNS servers have a default TTL of 3600 seconds.  This means that other DNS servers are instructed not to query our name server more frequently than every 3600 seconds or 1 hour for new DNS updates.

A certain TTL can be requested by creating a HelpDesk ticket or contacting us via email. Make sure to include the domain name in question as the new TTL requested. 

Note that the TTL is reset back to 3600 after changes are made to the host records.

2.  TLD Zone Update Intervals

Some TLD zones do not update in real time.  When you make a change to your nameserver listing in our control panel, we send the changes through to the registry almost instantly.   However, every TLD is controlled by its own registry and the registry determines how often they update the nameserver records for each domain.  For example for .com changes are updated in 3-5 minutes, whereas changes for .jp domains may take up to 24 hours.

3.  ISP DNS Caching

For efficiency, Internet Service Providers (ISPs) store name server and host record information in a DNS cache, and update that cache only every so often. A propagation delay is time between when a change is made to a domain's nameservers, and your local ISP next updates its DNS cache, thereby allowing to you see the change's effects. 

Our guideline for how often we'd like others to refresh their DNS cache for our records, is set to hourly. Whether or not such guidelines are followed by ISPs is strictly voluntary.

Please allow time for propagation to complete after changing the assigned nameservers, or changing host records for a domain.  Until propagation is complete, you will not be able to see the effects of those changes.

Propagation can take up to 48 hours, world-wide. The rate depends on your ISP. This is a true case of "up to", meaning it can finish in seconds, minutes, hours, or days.

If you switch to a different network, you might be able to see the changes you made.  For example, if you update the nameservers on your desktop computer, you can switch your phone from the wifi network to the cellular network to see the changes. 

You can also use sites like the DNS Checker to check how far the changes have propagated.

4.  Your PC's DNS Caching

On some rare occasions, the address may actually be cached by software on your PC.  To "flush" any cached DNS records, please do the following:


Windows

From a command prompt, enter the following command:

ipconfig /flushdns


Mac

For Mac OSX Leopard and above, enter the following command from a bash prompt:

dscacheutil -flushcache

For Mac OSX 10.5.1 and before, enter the following command from a bash prompt:

lookupd -flushcache


Linux

Restart the NSCD daemon by entering the following command from a bash prompt:

/etc/init.d/nscd restart

To determine if any of the above issues are affecting your domain, you can use a third-party online utility, such as whatsmydns.net.  From there you can do a DNS Lookup on your domain name and see the propagation results from different regions and DNS hosts.  In the drop-down menu, you can choose to search for "A" to find the IP address the domain is pointing to, and you can also choose to search for "NS" to find the DNS (namerservers) the domain is pointing to (usually in the format ns.examplednshost.com). If the records for the domain are not fully propagated, you may need to let 48 hours elapse to allow for propagation delay.