BIND SOA Configuration on a Sub Domain
 

Hello,

I was hoping someone could help me solve this problem with BIND, SOAs and Sub Domains

I have the following domain

mydomain.co.uk
NS = ns1.provider.com
NS = ns2.provider.com
SOA = ns1.provider.com
A = ns1.mydomain.co.uk 1.1.1.1
A = ns2.mydomain.co.uk 2.2.2.2

I have created a subdomain -

subdom.mydomain.co.uk
NS = ns1.mydomain.co.uk
NS = ns2.mydomain.co.uk

A Records should be handled by ns1/2.mydomain.co.uk for the subdom.mydomain.co.uk and www.subdom.mydomain.co.uk

The problem is that when I do a lookup against subdom.mydomain.co.uk its not getting an authoritive answer as it seems to be getting the SOA from the root/parent domain (mydomain.co.uk)

I've been doing a bit of googling and saw some suggestions of using glue records but was told by my provider that Nominet doesnt support them.

Ultimatly my end goal is to not change anything in mydomain.co.uk (except adding records pointing to subdomains) and have subdom.mydomain.co.uk getting A records from ns1.mydomain.co.uk and ns2.mydomain.co.uk

I would post the zone files but I dont have access to them.

Any help much appreciated!

Pete

Hi,

Unless it's a typo, you have a wrong SOA for your domain. It should be
If I can understand well what you are trying to do, you need to add an $ORIGIN for the subdomain(s) in the mydomain.co.uk zone file. If you don't have access there is no other way to do what you're trying to accomplish.
Anyway, the zone file for the TLD, should look like this:
And configure ns1/2.mydomain.co.uk to do what you want (add A RRs for subdom.mydomain.co.uk, www.subdom.mydomain.co.uk etc)

Regards

@bathory

The SOA should be

as you have mentioned in your example config.?
or @Pete-L
This might help you

Hi,

Thanks for the reply, I've spoken to my provider and they have given me the zone file.

Basically we are trying to use DNS load balancers (they serve the A Records) for the subdom.mydomain.co.uk while keeping the DNS management for the mydomain.co.uk with the provider and their web GUI. Would this be why the SOA is ns1.provider.com?

While I dont have direct access to the files to change myself I can specify changes to the provider and they can add them for me (they told me what I wanted to do wasnt possible, hence the post here as I found it hard to believe)

So from my understanding of what you're saying the zone file should look like (excluding the query regarding the root SOA)-

Many Thanks,
Pete

Its really confusing me
but as per my knowledge there should be an A record pointing "ns"

You can always wait for the experts review:hattip:

Wouldnt that make it ns1.subdom.mydomain.co.uk and ns2.subdom.mydomain.co.uk if specified under the subdom.mydomain.co.uk?

The name server which is mentioned is pointing to So how will it take But as I said you can wait for an expert's advice before making any changes

@deep27ak, @Pete-L

Don't be confused from the SOA word in the first line of a SOA record. The SOA RR is the whole stuff from the TTL to the closing ")". In the line
there is the @ (or the ORIGIN, i.e. the domain), the authoritative nameserver and the admin's email, so the above is correct.

In the above zone file, the lines in bold are the same as if you use the $ORIGIN, so you don't need both. But it's good practice to keep the domain and the subdomain(s) that are to be managed by a different dns, separated. So better use:

Hmmm strange so it looks like its configured ok then as this is what is currently configured (if a little untidy) -

When I do the following

it doesnt return any results

however when I do

it returns -

Name: subdom.mydomain.co.uk
Address: 5.5.5.5

I don't see any A RR for subdom.mydomain.co.uk. Is this the correct IP?
What give the following:

also post the output of

@bathory

"dig ns mydomain.co.uk" gives
"dig ns subdom.mydomain.co.uk" gives
@deep27ak

"dig -x 1.1.1.1" gives
"dig -x 2.2.2.2" gives
Cheers folks

So, it works.
From the 2 dig outputs, ns1/2/5/6.provider.com are the authoritative nameservers for mydomain.co.uk and ns1/2.mydomain.co.uk are the authoritative nameservers for subdom.mydomain.co.uk.
Now you need to configure the zone file(s) in ns1/2.mydomain.co.uk to add the A RRs for www.subdom.mydomain.co.uk and so on.

Regards

@bathory

The A records are handled by the load balancers, would this say to you that they arent serving the correct records when ns1/2.mydomain.co.uk gets queried?

Best Regards,
Pete

By load balancers, you mean ns1/2.mydomain.co.uk?
If so, then yes, they should answer authoritatively when queried for subdom.mydomain.co.uk and hosts in that subdomain. Try some queries using dig an see if you get the correct answers:
Regards