DNS record optimization

depricated

Are the DNS records created by cPanel necessary as is or can they be improved? In particular:

1) In addition to the domain name there are records for subdomains such as: cpanel, cpcalendars, cpcontacts, ftp, webdisk, webmail, whm, mail, www. Can/should this list be trimmed down?

2) Many of the above are A records with the domain's IP hard coded repeatedly. Could they all be converted to CNAME records, with just the domain having an A record with the IP?

WSS

mail. should never be a CNAME. Plenty of people do it, but you're not supposed to. I'm sure most are made A records for CPanel's code-reuse, so it doesn't have to parse the zone and figure out what to do when it can just do a regex sweep replace.

ftp/www/webmail should likely be left. I haven't used any of the others, but I bet there's an Outlook-like reason behind them.

depricated

WSS said: mail. should never be a CNAME. Plenty of people do it, but you're not supposed to.

That's funny. cPanel has mail. as CNAME by default for me.

WSS

@depricated said:

WSS said: mail. should never be a CNAME. Plenty of people do it, but you're not supposed to.

That's funny. cPanel has mail. as CNAME by default for me.

CPanel never was very good at following directions. (10.3, fwiw)

bsdguy

@depricated said:

WSS said: mail. should never be a CNAME. Plenty of people do it, but you're not supposed to.

That's funny. cPanel has mail. as CNAME by default for me.

In other words: cpanel has it reliably maximum idiotically wrong.

depricated

WSS said: CPanel never was very good at following directions. (10.3, fwiw)

10.3 refers to MX records (which in cpanel lists the domain name as the destination). What is the difference between the MX and mail entries?

WSS

@depricated said:

WSS said: CPanel never was very good at following directions. (10.3, fwiw)

10.3 refers to MX records (which in cpanel lists the domain name as the destination). What is the difference between the MX and mail entries?

Seriously?

One is an A record, one is a CNAME. If you are using "mail.foo.org" as an MX record and MAIL points to a CNAME rather than an A record, you're doing it wrong.

depricated

Confused. "is a X record" and "points to a X record" mean different things to me.

Example of a setup:

record name/type/value

foo.org/A/xx.xx.xx.xx
mail.foo.org/CNAME/foo.org
foo.org/MX/foo.org

WSS

MX record should not point to a CNAME, but something that resolves via A record; not that MX needs to be an IP address; an MX to name to CNAME to A record are recursive lookups. Everything pretty much handles it, but it's not what you're supposed to do. Like DNS glue, but without the glue.

bsdguy

@depricated

You can look at it like this: an MX record is meant for another machine (namely another mail server). So, whether it's called 'some-123-tech-taxonomy-456.some.dom' or 'smtp.some.dom' is meaningless. What, however, is meaningful is to keep the lookup short, simple, and efficient.

users and mail clients are a completely different thing. For them one usually wants something like 'mail.some.dom' - and that can be done without any problem because that's another "access path" to the mail server.

So you could and should do something like

$ORIGIN some.dom.

    IN  MX  10  server123

mail    IN  CNAME   server123

server123    IN      A  100.101.102.123

Such, you have a cname free direct MX record and still a "friendly" cname to tell users to put into their email client config.

depricated

Thanks for the examples and explanation @bsdguy

I think the earlier posts were just a misunderstanding between "is" and "points to". What you described seems to be the same as cpanel's DNS configuration:

• MX record which points to a server defined by an A record

• mail is a CNAME record which points to a server defined by an A record

Note that there is also a "webmail" subdomain which a user can use to reach webmail. I don't know what "mail" is.

depricated

To answer my initial question, those automatically generated subdomains are apparently called proxy subdomains:

Proxy subdomains provide access to cpsrvd over the standard http and https ports. They also provide configuration information for mail, calendar, and contact clients. https://documentation.cpanel.net/display/CKB/Proxy+Subdomains+Explanation

I have no plans to use cpcontacts, cpcalendars, webdisk, or whm (not reseller), but I guess I won't mess with them (for now..). Also I suppose there's a reason they are A records and not CNAME.

WSS

@depricated said:
To answer my initial question, those automatically generated subdomains are apparently called proxy subdomains:

Proxy subdomains provide access to cpsrvd over the standard http and https ports. They also provide configuration information for mail, calendar, and contact clients. https://documentation.cpanel.net/display/CKB/Proxy+Subdomains+Explanation

I have no plans to use cpcontacts, cpcalendars, webdisk, or whm (not reseller), but I guess I won't mess with them (for now..). Also I suppose there's a reason they are A records and not CNAME.

@WSS said:
mail. should never be a CNAME. Plenty of people do it, but you're not supposed to. I'm sure most are made A records for CPanel's code-reuse, so it doesn't have to parse the zone and figure out what to do when it can just do a regex sweep replace.

ftp/www/webmail should likely be left. I haven't used any of the others, but I bet there's an Outlook-like reason behind them.

You're welcome.

jar

@depricated said:

WSS said: mail. should never be a CNAME. Plenty of people do it, but you're not supposed to.

That's funny. cPanel has mail. as CNAME by default for me.

Yeah but there's wrong and then there's what I'll call "nerd wrong." Does it work? Then it's fine. Whether or not you complied with every RFC will not generally be mentioned in your obituary.

WSS

@jarland said:
Yeah but there's wrong and then there's what I'll call "nerd wrong." Does it work? Then it's fine. Whether or not you complied with every RFC will not generally be mentioned in your obituary.

file

The world isn't built on RFCs but the implementations and thus the interpretations of those who implemented them. That's what people (talking in the general sense in regards to RFC) have to strive to work with. Reality sucks. As does the use of "SHOULD" in RFCs.

Clouvider

@jarland said:

@depricated said:

WSS said: mail. should never be a CNAME. Plenty of people do it, but you're not supposed to.

That's funny. cPanel has mail. as CNAME by default for me.

Yeah but there's wrong and then there's what I'll call "nerd wrong." Does it work? Then it's fine. Whether or not you complied with every RFC will not generally be mentioned in your obituary.

MX record is not pointed to the mail CNAME, it points to the domain’s A record, so it’s done right.

Mail is used in configuration for mail clients.

Webmail is used to redirect to the cPanel Managed webmail System.

I don’t get this whole bitching on cPanel.

WSS

@Clouvider said:

@jarland said:

@depricated said:

WSS said: mail. should never be a CNAME. Plenty of people do it, but you're not supposed to.

That's funny. cPanel has mail. as CNAME by default for me.

Yeah but there's wrong and then there's what I'll call "nerd wrong." Does it work? Then it's fine. Whether or not you complied with every RFC will not generally be mentioned in your obituary.

MX record is not pointed to the mail CNAME, it points to the domain’s A record, so it’s done right.

Mail is used in configuration for mail clients.

Webmail is used to redirect to the cPanel Managed webmail System.

I don’t get this whole bitching on cPanel.

This was figured out several days ago, but thanks for weighing in.

Clouvider

No probs. :-)