I have a my site on test.domain.com which was pointing to dedicated server IP (e.g. 12.12.12.12). Earlier it was with X name servers.
I bought a new hosting so I updated the name servers to point to Y name servers. Now, when I pointed to Y name servers, my emails stopped working so I reverted back to X name servers and changed the test.domain.com to point to my new dedicated server IP (e.g. 13.13.13.13).
Now, what is happening is that when I browse my test.domain.com, its pointing to 12.12.12.12 in some of the machines and its pointing to 13.13.13.13 in some other machines.
Its been 16 hours since I changed this settings. I know it normally takes maximum of 24 hours to propagate across the globe but I want to know,
Please help.
Can there be any other problem regarding this?
You may face service (Web and emails) outages in certain countries where refresh rate of DNS resolvers is low (once per day). Your website might not accessed in these countries and emails cannot be reached to you.
Is this because of DNS caching?
Yes, it is because of DNS caching. If you wish you can control TTL (Time To Live) value of each DNS record in your domain name's zone file. TTL is a number of seconds that a DNS resolver is allowed to cache a zonefile before asking for a new copy of that zonefile.
Normally, this value is set at 14400 seconds, or 4 hours. When you want to change the DNS changes, you should decrease the TTL value to 300 seconds, or 5 minutes. Shorter TTL settings can increase propagation speed. Though some ISPs (Internet Service Providers) do not honor TTLs, and instead refresh their resolvers’ DNS cache once per day. Unfortunately, lowering TTLs does not lower the propagation time for such resolvers.