This is probably our most commonly asked question. Unfortunately, the answer is not a simple one since there are multiple factors at play and very few of which are within our control. We have provided a basic explanation below as well as a few resources you can use to verify that your name server changes have been made correctly.
First, we make name server changes in real-time. This means there are absolutely no delays on our end. Again, when you update name servers with our service, the change is made immediately. So what exactly is changed? Two things: 1) your whois information is updated to reflect the name server change and 2) the registry running the respective TLD zone file is informed to update the name servers in the zone file (also done near-real-time). In short, we do everything in our power to make the change as quickly as possible - there are no delays on our end.
However, while the name server updates are real-time, DNS records are cached across the Internet at different times. Because DNS records are cached with different expiration times across the Internet, the name server changes will take effect at different times depending on where on the Internet you look up your domain's respective hostnames (i.e. www.domain.com). This seemingly random delay between the update of name servers and the time in which that update actually takes effect results in us receiving lots of questions. As a rule of thumb, it takes anywhere between 1-48 hours.
Let's use a simplistic example to illustrate how this delay occurs. You own the domain "domain.com". The first time you ever typed in www.domain.com, your computer immediately requested the IP address associated with www.domain.com. That IP address is provided by your domain's name servers. Your ISP caches (stores a local copy) the IP address retrieved from your domain's name servers as well as the name server themselves. It caches the IP address and your domain's name servers locally since this makes the Internet much faster. How long your ISP stores that IP address and your domain's name servers locally depends on a number of factors.
Now when you change your domain's name servers, the new name servers may very well serve a different IP address for www.domain.com, so you would expect that when you type in www.domain.com, the new address would be used; however, your ISP more than likely is serving the local copy that your old name servers provided. It will not serve the updated address from the new name servers until the ISP's cached records associated with www.domain.com have expired. Those cached records typically expire anywhere from 1-48 hours - it varies from ISP to ISP due to a multitude of factors.
The other thing to keep in mind is that your web browser may be set to cache web sites similar to how ISPs do so in the description above. We therefore highly recommend clearing your web browser cache when testing name server changes. Here is a link to an article by Google covering how to clear browser cache for popular browsers.
To follow-up with the propagation status of your domain, you can visit DNSChecker website, then enter your domain in the specified field and check if the returned results correspond with one of our servers' IP addresses (will be outlined in the New Account Information email sent to).