DNS
What is it?
- Domain Name System (DNS)
- The phonebook of the Internet
- A lookup from human readable text to Internet Protocol (IP) addresses
Resource: https://www.cloudflare.com/learning/dns/what-is-dns/
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Many kinds of DNS records
- https://en.wikipedia.org/wiki/List_of_DNS_record_types
- Most common / important ones
- A: translates to IPv4 address (e.g. 192.0.2.1)
- AAAA: translates to an IPv6 address (e.g. 2001:0db8:85a3:0000:0000:8a2e:0370:7334)
- CNAME: an alias for another domain (e.g. custom.intercom.help)
- TXT: just text value used for things like authentication
- MX: for setting up email servers (e.g. ASPMX.L.GOOGLE.COM)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5722937/pasted-from-clipboard.png)
Many kinds of DNS records
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771595/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771598/pasted-from-clipboard.png)
What makes up a DNS record?
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Most common parts
- Type
- Host: which subdomain is it active on
- Value: what is the value of the record
- TTL: how long should it should be cached/valid for before asking for the latest value
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771606/pasted-from-clipboard.png)
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Layers like an onion
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771488/pasted-from-clipboard.png)
Layers like an onion
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771488/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771480/pasted-from-clipboard.png)
Layers like an onion
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771488/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771484/pasted-from-clipboard.png)
Layers like an onion
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771488/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771486/pasted-from-clipboard.png)
Which DNS server?
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771486/pasted-from-clipboard.png)
- Nameservers
- Configured in domain registrar
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771566/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771572/pasted-from-clipboard.png)
How to tell which DNS server?
- MXToolbox is your friend
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771581/pasted-from-clipboard.png)
MXToolBox is a very very good friend
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771588/pasted-from-clipboard.png)
Other tools
- dig
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771723/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771729/pasted-from-clipboard.png)
Other tools
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771732/pasted-from-clipboard.png)
Help Centers & HTTPS Custom Domain
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771733/pasted-from-clipboard.png)
- Help Center is hosted on our servers
- Our certificate is only valid for *.intercom.help domains
Help Centers & HTTPS Custom Domain
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771634/pasted-from-clipboard.png)
Help Centers & HTTPS Custom Domain
- Regular CNAME investigations not fully valid for these cases
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771652/pasted-from-clipboard.png)
Help Centers & HTTPS Custom Domain
- Because in this system in the middle between the end user and actual website
- It can handle all requests at the root domain level and have internal configurations to direct the subdomain to the appropriate location without needing a DNS record
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771655/pasted-from-clipboard.png)
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771634/pasted-from-clipboard.png)
Typical problems
- Setting the wrong value
- Using something like `theirdomain.intercom.help` or `intercomworkspacename.intercom.help` instead of `custom.intercom.help`
- Setting up the wrong domain servers
- Not following all instructions in our custom setup
Some examples
1. Why isn't `help.timothyandruth.com` working? See my settings below
2. I set up `docs3.thewheatfield.org`. Why isn't it working?
![](https://s3.amazonaws.com/media-p.slid.es/uploads/87792/images/5771711/pasted-from-clipboard.png)
Set up your own custom help center
- Log into Namecheap via 1Password
- Create your own CNAME and set it up on your own help center
Let's try set up Cloudflare
What could possibly go wrong? 😂
DNS
By Timothy Lim
DNS
- 1,277