Q: How do I create a TXT record?

Strontium90 wrote a good answer for this in another string:

https://discussions.apple.com/thread/5888316

It describes Server.app 3 for Mavericks but the same applies for Server.app 4 in Yosemite.

All (well, nearly al) of Server's files are in the /Library/Server directory. The BIND files are in /Library/Server/named.

There is a file called /Library/Server/named/.version that says the BIND version (on Yosemite) is

BIND 9.9.5 (Extended Support Version)

If you want to add TXT to an entry that has an A record (or an AAAA record)

• Select Show All Records from the settings menu at the bottom of the DNS pane.
• Select the machine entry for the record you want to edit
• Select Edit Record
• Fill in the Text field

Thank you for the explanation, but I still don't see what I have to do exactly where to make the TXT entry with underscore work.

I am trying to set up Caching Server for our two load balanced lines according to this great article: http://blog.fraserhess.com/2014/10/caching-server-enterprise-edition.html

unfortunately the DNS part is shown for Windows Server where it seems to work. In my case the DNS is provided by the same Server.app that also runs the Caching Server. As hemmes said the Server.app GUI refuses the underscore, but I am missing the information how and where to modify this manually...

Can anybody help?

thank you Mike, I would be very grateful

I prefer nano, but can also handle vi a bit. At least I know how to :q

No seriously, I am very familiar with the command line but I hardly had to do with DNS setup further than setting A or MX records through different GUI.

simon@ifoam wrote:

 

I prefer nano, but can also handle vi a bit. At least I know how to :q

 

No seriously, I am very familiar with the command line but I hardly had to do with DNS setup further than setting A or MX records through different GUI.

If your familiar with the command line then adding a TXT record, even one beginning with an underscore would simply be a matter of inserting a line similar to the following

_domainkey.domain.com.               10800 IN TXT      "t=y; o=~; r=postmaster@domain.com"

this needs to go in to -

/Library/Server/settings/named/db.domain.com

where db.domain.com will be the file corresponding to the domain name aka. zone name you have defined in Server.app.

Note: As should be obvious the example above is not for Apple's Caching server but rather for use with DomainKeys. You just need to put your requirements in the corresponding places.

Thank you very much. It works to set up the TXT entry like that, but as it absolutely didn't want to work I dug deeper and it seems I am in a scenario which still is not supported:

Multiple public IP addresses and NAT.

Another person came to the same conclusion here:Re: Use caching server with multiple public Addresses?

I found out that these help pages actually describe what I was asking for in the first place.

http://help.apple.com/serverapp/mac/5.0/#/apdC36C9994-1533-4DCB-9CFF-870CB0FADCD B

http://help.apple.com/serverapp/mac/5.0/#/apd6015d9573

I noticed later the headline "DNS settings for caching without a NAT" in the second article

As far as I am aware the ability to use multiple public IP addresses was added in Server 4.x i.e. Yosemite. As I understand it this basically boils down to creating a TXT record which defines the multiple public IP addresses that client Macs might connect to the Internet via and for which you want your single caching server to respond.

See http://blog.fraserhess.com/2014/10/caching-server-enterprise-edition.html

I do not see NAT being a problem, not using NAT would be more of a problem which is why that is specifically discussed in the Apple articles you linked to.

A possible real world scenario might be a company using multiple bonded Internet links - each has its own public IP address but all are 'bonded' in to one link as far as your LAN is concerned. Therefore your LAN is a single NATed range using multiple public IP addresses. The Apple caching server would be on the same LAN and like the clients could go out to the Internet via any of those public IP addresses - hence the need to define a TXT record to say which ones it is responsible for.

So depending on what and how many public IP addresses the following is a possible example I believe should suit you.

_aaplcache._tcp 259200 IN TXT "prs=65.125.164.33-65.125.164.44"

or

_aaplcache._tcp 259200 IN TXT "prs=65.125.164.33,65.125.164.44"

The first does a range of IP addresses, the second example does two individual IP addresses.

Thank you again for the explanation. I also thought it should still work, but I can't get it to work. Of course I restarted DNS service to apply changes.

The remaining thing I can think of now is this from the help article:

The DNS TXT record needs to be added to the zone that:

• Is authoritative for the domain
• Matches the default search domain for network clients
  

First of all I want to underline that I am not a DNS expert. I'm just trying to describe the situation as I see it.

The OS X Server with DNS and Caching Server is #1 used by the clients, but they don't have a search domain set.

Our server manages a couple of internal .dev domains and apart from that has a zone which corresponds to the server's own hostname. The latter I thought would be the right one to add the TXT record.

However after doing so nothing changes on the client computers. AppStore downloads which surely are in the Cache are requested from the internet.

I tried setting the search domain on the client computer (to xxx.company.org which corresponds to the zone I have modified). Cleared clients DNS cache. No change.

I monitored from a client computer with tcpdump what DNS request are being sent when e.g. starting iMovie download in AppStore, but I don't even see anything related to _applcache._tcp

Maybe my scenario really is a problem for the caching service? Sorry for hijacking this thread. First I thought it's closely related, now it seems I might be in a very unusual situation.