Dns

Few days back I visited Official Google Apps forum (one of my favorite places) and answered many questions. It was quite after some time i was there and found few cases/questions/problems as really interesting. Here’s one of the questions asked there by a admin named aol985 about SPF records.

His question:

As described in http://www.google.com/support/a/bin/answer.py?hl=en&answer=33786 , I set SPF record for mashfilm.ru domain to “v=spf1 include:aspmx.googlemail.com ~all”. But aspmx.googlemail.com currently does not resolves. Is it correct?

After recieving lots of emails regarding SRV records issue in Google Apps I must say that Google has missing info in their documentation about SRV records. As per refering to official Google’s help here.

It has missing info. about the location servers. Here are those missing SRV records…

client._tcp.YOURDOMAIN.TLD. IN SRV 5 0 5222 talk.l.google.com. 
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk1.l.google.com. 
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk2.l.google.com. 
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk3.l.google.com. 
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk4.l.google.com.

So finally saying…..just forget everything and have these SRV records to get your domain’s Gtalk working from external IM services. Feel free to post for any issues.

Glue records

These are the mosy fundamental DNS record which actually start with the lookup. Let’s understand how to come in basic scenario…… Observe two sites - harisri.in & anuragbhatia.com There’s a basic difference in terms of DNS in both sites. Nameservers of harisri.in are ns1.anuragbhatia.com & ns2.anuragbhatia.com which belongs to a totaly seprate zone, but nameservers for anuragbhatia.com are ns1.anuragbhatia.com, ns2.anuragbhatia.com & so….. i.e domain is having nameservers which are sub zones of  domain itself.

Most of people face issue in using Google sites is redirection……i,e www.domain.com works fine (becoz of presence of cname record) BUT domain.com fails here…… SO lets see the possible ways out to the issue:

1. use redirection offered by Registrar (eNom, Godaddy, name.com etc…)
2. use redirection offered by third party dns hosts. (only redirection and NOT dns hosting)

In this post, i will consider #2 as for #1 instructions are already available (Google for them!) and also i guess most of you people are reading this post because you were unable to do the #1! since we are using free services, they are perfect for blogger, small biz sites (having low traffic…i.e less then 10,000 visitors per day) We can use any of following host for setting redirection:

Most of web host state that if you have changed your domain’s name server’s to there’s server then also it will take around 24-48 hours for DNS changes to propagate. That’s not completely true.

Correct sentence would be if you have changed your domain’s name server’s to theirs server then also it might take around 24-48 hours for DNS changes to propagate. Still that’s just a bit of “truth!” What I mean to say it’s just creates a wrong image of DNS working in eyes of a newbie. Let me be clear in one thing - There is NO such think like propagation between world dns server. That’s just a wrong picture. Now lets think over it and shoot it!