4 ms·

Understanding DNS Record Types

33 points by phikai 12y ago

ulysses 12y ago
"Blank Name - A record that has nothing in the name slot gets used for all requests made to the base/naked form of the domain." No, a blank name uses whatever name was used on the previous record. Near the top of the zone file, that name is usually the domain name because of the SOA record. But later on, it won't be.
- grhmc 12y ago
  Seems implementation specific. BIND does this you're right, but many services don't follow the rule as closely.
  - ulysses 12y ago
    Actually, from RFC 1035, section 5.1: "If an entry for an RR begins with a blank, then the RR is assumed to be owned by the last stated owner." https://www.ietf.org/rfc/rfc1035.txt https://www.ietf.org/rfc/rfc1035.txt
drinchev 12y ago
I don't think this article is technically deep enough to be of any significant value ( at least for me ). Not discussed at all ( and that people interested in the topic should know ) : 1. NS, SOA records 2. What exactly is TXT record. 3. What's the difference between CNAME, A Records Later on I also checked the first article [1], which even doesn't explain what TLD is. [1] https://pressable.com/blog/2014/12/04/dns-management-basics/ https://pressable.com/blog/2014/12/04/dns-management-basics/
- phikai 12y ago
  We'll be deep diving on specific record types and their uses next week.
tuacker 12y ago
One thing I've been wondering for a while and haven't found a answer to. Providers like Digital Ocean let you use their nameservers. Why would I do this over just using the registrars nameservers?
- phikai 12y ago
  A lot of that has to do with features and quality of the service. If you have advanced DNS needs (failover, traffic directing, etc) you may need to use a third party. If you have very basic needs sometimes the host can provide those easily for you. Additional conversation: http://stackoverflow.com/questions/8605200/settings-dns-records-with-hosting-company-or-registrar http://stackoverflow.com/questions/8605200/settings-dns-reco...
welly 12y ago
A question regarding TTL. If changing the TTL value of a record will speed up (for want of a better word) when that record is available to the DNS server, why would you ever set the TTL to 3600 or more? I understand that there is some kind of caching going on but I don't actually fully understand TTL and what is ideal. Any advice/insights/explanations appreciated!
- phikai 12y ago
  A lot of that has to do with costs and service levels provided by your DNS provider. There's a couple of good points at Server Fault: http://serverfault.com/questions/388289/what-are-the-benefits-of-a-high-ttl-for-dns http://serverfault.com/questions/388289/what-are-the-benefit...

33 points by phikai 12y ago

"Blank Name - A record that has nothing in the name slot gets used for all requests made to the base/naked form of the domain." No, a blank name uses whatever name was used on the previous record. Near the top of the zone file, that name is usually the domain name because of the SOA record. But later on, it won't be.

grhmc 12y ago
Seems implementation specific. BIND does this you're right, but many services don't follow the rule as closely.
- ulysses 12y ago
  Actually, from RFC 1035, section 5.1: "If an entry for an RR begins with a blank, then the RR is assumed to be owned by the last stated owner." https://www.ietf.org/rfc/rfc1035.txt https://www.ietf.org/rfc/rfc1035.txt

drinchev 12y ago

I don't think this article is technically deep enough to be of any significant value ( at least for me ). Not discussed at all ( and that people interested in the topic should know ) : 1. NS, SOA records 2. What exactly is TXT record. 3. What's the difference between CNAME, A Records Later on I also checked the first article [1], which even doesn't explain what TLD is. [1] https://pressable.com/blog/2014/12/04/dns-management-basics/ https://pressable.com/blog/2014/12/04/dns-management-basics/

phikai 12y ago
We'll be deep diving on specific record types and their uses next week.

tuacker 12y ago

One thing I've been wondering for a while and haven't found a answer to. Providers like Digital Ocean let you use their nameservers. Why would I do this over just using the registrars nameservers?

phikai 12y ago
A lot of that has to do with features and quality of the service. If you have advanced DNS needs (failover, traffic directing, etc) you may need to use a third party. If you have very basic needs sometimes the host can provide those easily for you. Additional conversation: http://stackoverflow.com/questions/8605200/settings-dns-records-with-hosting-company-or-registrar http://stackoverflow.com/questions/8605200/settings-dns-reco...

welly 12y ago

A question regarding TTL. If changing the TTL value of a record will speed up (for want of a better word) when that record is available to the DNS server, why would you ever set the TTL to 3600 or more? I understand that there is some kind of caching going on but I don't actually fully understand TTL and what is ideal. Any advice/insights/explanations appreciated!

phikai 12y ago
A lot of that has to do with costs and service levels provided by your DNS provider. There's a couple of good points at Server Fault: http://serverfault.com/questions/388289/what-are-the-benefits-of-a-high-ttl-for-dns http://serverfault.com/questions/388289/what-are-the-benefit...