DHCP Scope and DNS Reverse Lookup

gjacobse

In setting up my recent Nextcloud instance, I have it available externally. While I still need to get a Cert for it, I have some local internal members testing it.

However after creating the A Record for it, they are not able to access it. The IP is pingable, so it's not a block of any sort. It's not pingable by nextcloud.domain.com.

In reviewing the DNS Reverse lookup I have:

1.168.192.in-addr.arpa
2.168.192.in-addr.arpa

However the NextCloud instance is on a 168.3.x zone. Going back to DHCP, the single scope is 168.1.1 - 168.3.254.

I believe I have a few options here.

force NextCloud to a 168.2.x address.
add the zone in DNS
Update the DHCP scope.

I'm leaning towards pushing the NextCloud instance to the 168.2.x,...

Thoughts?

Dashrender

What does Reverse DNS have to do with forward DNS not working, assuming that part is correct.

Can you ping the DNS name? You said you could ping the IP.

scottalanmiller

I have a feeling that the issue is that port forwarding has not been done yet?

gjacobse

@dashrender said in DHCP Scope and DNS Reverse Lookup:

What does Reverse DNS have to do with forward DNS not working, assuming that part is correct.

Can you ping the DNS name? You said you could ping the IP.

It is not pingable by nextcloud.domain.com

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

I have a feeling that the issue is that port forwarding has not been done yet?

It is available externally just fine. it is internal that I am having the issue. I don't believe Port Forwarding applies in this case - unless I"m missing something.

scottalanmiller

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@dashrender said in DHCP Scope and DNS Reverse Lookup:

What does Reverse DNS have to do with forward DNS not working, assuming that part is correct.

Can you ping the DNS name? You said you could ping the IP.

It is not pingable by nextcloud.domain.com

That didn't make it any clearer.

scottalanmiller

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

gjacobse

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

DNS Manager
Forward Lookup Zone - domain.com A Record(s)

demo ( points to external IP)
RDS (points to internal IP)
RDS3 (points to Internal IP)
nextcloud (points to Internal IP)

scottalanmiller

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

DNS Manager
Forward Lookup Zone - domain.com A Record(s)

demo ( points to external IP)
RDS (points to internal IP)
RDS3 (points to Internal IP)
nextcloud (points to Internal IP)

If the external DNS points to an internal IP, it can't work.

Dashrender

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

Unless your firewall supports hairpinning, assuming that's a Scott approved term.

stacksofplates

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

DNS Manager
Forward Lookup Zone - domain.com A Record(s)

demo ( points to external IP)
RDS (points to internal IP)
RDS3 (points to Internal IP)
nextcloud (points to Internal IP)

What DNS manager? Internal or external?

Instead of looking at reverse, what do you get from an nslookup on nextcloud.domain.com?

scottalanmiller

@dashrender said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

Unless your firewall supports hairpinning, assuming that's a Scott approved term.

Even hairpinning doesn't work in this direction.

gjacobse

@stacksofplates said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

DNS Manager
Forward Lookup Zone - domain.com A Record(s)

demo ( points to external IP)
RDS (points to internal IP)
RDS3 (points to Internal IP)
nextcloud (points to Internal IP)

What DNS manager? Internal or external?

Instead of looking at reverse, what do you get from an nslookup on nextcloud.domain.com?

DNS Manager : Server 2012

scottalanmiller

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@stacksofplates said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

DNS Manager
Forward Lookup Zone - domain.com A Record(s)

demo ( points to external IP)
RDS (points to internal IP)
RDS3 (points to Internal IP)
nextcloud (points to Internal IP)

What DNS manager? Internal or external?

Instead of looking at reverse, what do you get from an nslookup on nextcloud.domain.com?

DNS Manager : Server 2012

OH! You should have said that, we've been assuming the main DNS system. Argh.

So internal doesn't work even though it points to the right address?

scottalanmiller

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

However the NextCloud instance is on a 168.3.x zone. Going back to DHCP, the single scope is 168.1.1 - 168.3.254.

force NextCloud to a 168.2.x address.

What do you mean force it to 168.2.x? That is a 168.3.x address here. See your subnet notes above.

gjacobse

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@stacksofplates said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

It is available externally just fine. it is internal that I am having the issue.

Then why are we looking at the public DNS records? You either need to assign an overloaded one internally or a different one internally. The internal users cannot be using the public DNS records.

DNS Manager
Forward Lookup Zone - domain.com A Record(s)

demo ( points to external IP)
RDS (points to internal IP)
RDS3 (points to Internal IP)
nextcloud (points to Internal IP)

What DNS manager? Internal or external?

Instead of looking at reverse, what do you get from an nslookup on nextcloud.domain.com?

DNS Manager : Server 2012

OH! You should have said that, we've been assuming the main DNS system. Argh.

So internal doesn't work even though it points to the right address?

Guess I made some assumptions when I mentioned DHCP Scope and DNS, and refererenced IPs in the local 192.168.2 zone

gjacobse

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

However the NextCloud instance is on a 168.3.x zone. Going back to DHCP, the single scope is 168.1.1 - 168.3.254.

force NextCloud to a 168.2.x address.

What do you mean force it to 168.2.x? That is a 168.3.x address here. See your subnet notes above.

NextCloud currently has a 192.168.3.x address. Force as in push it to a 192.168.2.x address

scottalanmiller

I am so lost.

stacksofplates

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

I am so lost.

Ya idk what's going on. I'd do an nslookup first to figure out what the clients are tying to get to.

scottalanmiller

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

However the NextCloud instance is on a 168.3.x zone. Going back to DHCP, the single scope is 168.1.1 - 168.3.254.

force NextCloud to a 168.2.x address.

What do you mean force it to 168.2.x? That is a 168.3.x address here. See your subnet notes above.

NextCloud currently has a 192.168.3.x address. Force as in push it to a 192.168.2.x address

Whoa, that's nothing like what you had before. 168.x is external public IPs. 192.168.x is internal, private IPs.

Why are there two subnets as options?

stacksofplates

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

@scottalanmiller said in DHCP Scope and DNS Reverse Lookup:

@gjacobse said in DHCP Scope and DNS Reverse Lookup:

However the NextCloud instance is on a 168.3.x zone. Going back to DHCP, the single scope is 168.1.1 - 168.3.254.

force NextCloud to a 168.2.x address.

What do you mean force it to 168.2.x? That is a 168.3.x address here. See your subnet notes above.

NextCloud currently has a 192.168.3.x address. Force as in push it to a 192.168.2.x address

Whoa, that's nothing like what you had before. 168.x is external public IPs. 192.168.x is internal, private IPs.

Why are there two subnets as options?

This is why I was confused. Looks like he left off the 192 to shorten it? I thought it was public also.

Ah it's in the reverse ip. I just missed it.