dns reverse

to do the reverse dns domain shackvirtual.com.br for ips 177.1.138.45 177.1.138.46 and the company that gave me the ips informed me that I do a local configuration in / etc / named.conf. and add the in-addr.arpa PTR and I did as I found a tutorial but not worked. I'm all ready with the vms but I can not configure the location of reverse. I know this is not part of the support cloudmin but I have no else to turn and wonder if you guys could help me. thank you

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If so I can pay for this service ...

I myself haven't used Cloudmin before, and I know that Virtualmin doesn't manage reverse DNS zones, but you should be able to accomplish this easily with Webmin's BIND module. So this topic is probably even independent from Cloudmin.

I'm assuming your hoster configured a reverse NS delegation for those specific two IP addresses to your nameserver.

You can try this: Go to "Webmin / Servers / BIND DNS Server". Click on "Create master zone". Select "Zone type: Reverse". Enter "177.1.138" as zone name. Enter something as "Email address". Click "Create".

You're taken to the zone screen then. Click "Reverse Address" in the types table. Enter address "177.1.138.45" for Address and whatever you like for "Hostname". Set "Update forward" to "No". Click "Create". Repeat this for the other IP. Then click "Apply Zone" in the top-right.

Your BIND will then serve the proper reverse zone for your two IP addresses. One caveat: The local system won't be able to reverse-resolve other IPs from 177.1.138.* anymore, since the local BIND is responsible for them and has no information. It'd be a lot more hassle though to set it up differently. Reverse zones are usually only delegated on a per-/24 network basis.

You can test proper resolution with this command: dig -x 177.1.138.45 @your-nameserver-ip

If regular resolution doesn't work then, you'd need to give us more details about how your hoster set up the reverse delegation for you. There are several ways to do that; it is possible that your zone needs to be named differently and contain both A and PTR records. Can't say that without further info though.

I did some further DIGing and found out, that my method described above probably will not work. I can see that your hoster seemingly uses the RFC-2317 CNAME-A-PTR scheme to delegate single IP addresses. The relevant info is this:

138.1.177.in-addr.arpa. 86400 IN NS ns03-cta.brasiltelecom.net.br. 138.1.177.in-addr.arpa. 86400 IN NS ns04-bsa.brasiltelecom.net.br. ;; Received 109 bytes from 200.160.0.10#53(A.DNS.BR) in 227 ms   45.138.1.177.in-addr.arpa. 86400 IN CNAME 45.40-47.138.1.177.in-addr.arpa. 40-47.138.1.177.in-addr.arpa. 86400 IN NS ns1.shackvirtual.com.br. 40-47.138.1.177.in-addr.arpa. 86400 IN NS ns2.mktconnection.com.br. 40-47.138.1.177.in-addr.arpa. 86400 IN NS ns1.mktconnection.com.br. 40-47.138.1.177.in-addr.arpa. 86400 IN NS ns2.shackvirtual.com.br. ;; Received 171 bytes from 201.10.124.26#53(ns03-cta.brasiltelecom.net.br) in 284 ms

This means that the IP address is mapped to a CNAME entry instead of the usual PTR, and is pointing to "45.40-47.138.1.177.in-addr.arpa.". The nameservers for that zone are the hosts listed in the NS lines below.

Are "shackvirtual" and "mktconnection" hostnames of your servers? Did you receive the IPs .40 to .47, or only .45 and .46? There needs to be an NS delegation to your nameservers specifically for the IPs that you own, and I cannot see that so far.

I await the response virtualimin Thanks

sigh... I highly doubt that the Virtualmin team will/can tell you anything else besides what I said at this point. I DO have quite some experience with nameservers, you know.

Anyway, suit yourself and have fun waiting for the Vmin team, if you don't want my help. Sheesh. You should set your next support requests to "private" by the way, if you want replies only from the Vmin team, so that I don't waste any more time testing your stuff and typing in all this.

Do you have any objective solution to this problem?

Locutus provides quite a bit of valuable help around here, it's certainly worth looking into what he has to say :-)

But yeah, your issue is a bit outside the scope of Cloudmin Support, and we unfortunately don't provide consulting services. If you have questions that aren't related to Cloudmin, you can always ask in the forums to obtain assistance (which we monitor, along with wonderful folks like Locutus).

To help get you started though -- we can offer that it looks like your ISP delegated those two IP's to 45.40-47.138.1.177.in-addr.arpa and 46.40-47.138.1.177.in-addr.arpa.

So in Webmin (this is what Locutus was referring to), you would need to go to the BIND module and create a reverse zone for the network 177.1.138.40-47. And then in that zone, add PTR records for 45.177.1.138.40-47 and 46 that point to the hostnames you want those IP's to resolve to.

That's gets into DNS administration though... if that doesn't make sense when you read that, I might suggest the book "DNS and BIND" by O'Reilly, which does an awesome job at explaining DNS setup and management. But there are also plenty of online tutorials on DNS as well.

Hello Locutus

I made the recommended setting and get the following information on the command dig-x @ 177.1.138.45 shackvirtual.com.br

login as: root Access denied root@177.1.138.45 's password: Access denied root@177.1.138.45 's password: [root @ shackvirt ~] # dig-x @ 177.1.138.45 shackvirtual.com.br

; << >> DiG 9.8.2-9.8.2rc1-RedHat-0.10.rc1.el6_3.5 << >>-x @ 177.1.138.45 shackvirtual.com.br ;; Global options: + cmd ;; Got answer: ;; - >> HEADER << - opcode: QUERY, status: NOERROR, id: 31486 ;; Flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION: ; 45.138.1.177.in-addr.arpa. IN PTR

;; ANSWER SECTION: 45.138.1.177.in-addr.arpa. 38400 IN PTR ns1.shackvirtual.com.br.

;; AUTHORITY SECTION: 138.1.177.in-addr.arpa. 38400 IN NS shackvirt.cloudmin.tchod.com.

;; Query time: 0 msec ;; SERVER: 177.1.138.45 # 53 (177.1.138.45) ;; WHEN: Thu Nov 22 10:54:36 2012 ;; MSG SIZE rcvd: 122

[root @ shackvirt ~] #

I wonder if the line ......

;; AUTHORITY SECTION: 138.1.177.in-addr.arpa. 38400 IN NS shackvirt.cloudmin.tchod.com.

should not be ....

;; AUTHORITY SECTION: 138.1.177.in-addr.arpa. 38400 IN NS shackvirtual.com.br.

This correct this way?

thank you

$ host 177.1.138.45 Host 45.138.1.177.in-addr.arpa. not found: 3(NXDOMAIN)

Alright, I'm making the following assumptions:

  • Your hoster delegated the IPs 177.1.138.40 to 177.1.138.47 to you.
  • You are planning to operate four nameservers to host the reverse zones, on the IPs 177.1.138.43 .44 .45 .46 (that's what the delegation at your hoster points to)
  • You're setting up .45 as master and the others as slaves

On the .45, you create, like Eric correctly said, a reverse zone named "177.1.138.40-47". Webmin will automatically convert that to the correct format with the in-addr.arpa thing.

In that zone, for each of your IPs you want pointers for, you create two entries, an A and a PTR. That's required due to the CNAME scheme your hoster uses.

Webmin doesn't let you create A records in a reverse zone, because that is strictly speaking not supported, but still works. So you'll have to "Edit the Records File" manually and paste the following:

40.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.40 40.40-47.138.1.177.in-addr.arpa. IN PTR hostname_for_that_ip.domain.com 41.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.41 41.40-47.138.1.177.in-addr.arpa. IN PTR hostname_for_that_ip.domain.com [...] 47.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.47 47.40-47.138.1.177.in-addr.arpa. IN PTR hostname_for_that_ip.domain.com

That zone then needs to be propagated to your slave nameservers, e.g. through Webmin's DNS Cluster Slave feature, so that all nameservers that your hoster presents as responsible for your reverse zone have the same information.

If all of this was too much for you to understand, I'll have to agree with Eric that you probably should do some reading, books or online tutorials, first before you enter the world of DNS, which is not really trivial.

Which machine should I do this setup? In cloudmin system or virtual machine created?

What should I put the configuration file?

Forgive me my ignorance about reverse dns. It's the first time I am dealing with this matter.

Thank you for your cooperation

40.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.40 40.40-47.138.1.177.in-addr.arpa. IN PTR hostname_for_that_ip.domain.com 41.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.41 41.40-47.138.1.177.in-addr.arpa. IN PTR hostname_for_that_ip.domain.com [...] 47.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.47 47.40-47.138.1.177.in-addr.arpa. IN PTR hostname_for_that_ip.domain.com

Ok.Edit Records File in VM

/var/named/177.1.138.rev.

Without editing it this way:

$ttl 38400 138.1.177.in-addr.arpa. IN SOA shackvirt.cloudmin.tchod.com. guimaraesphp.hotmail.com. ( 1353599081 10800 3600 604800 38400 ) 138.1.177.in-addr.arpa. IN NS shackvirt.cloudmin.tchod.com. 45.138.1.177.in-addr.arpa. IN PTR ns1.shackvirtual.com.br. 46.138.1.177.in-addr.arpa. IN PTR ns2.shackvirtual.com.br.

That's how it should be?

$ttl 38400 138.1.177.in-addr.arpa. IN SOA shackvirt.cloudmin.tchod.com. guimaraesphp.hotmail.com. ( 1353599081 10800 3600 604800 38400 ) 138.1.177.in-addr.arpa. IN NS shackvirt.cloudmin.tchod.com. 45.138.1.177.in-addr.arpa. IN PTR ns1.shackvirtual.com.br. 46.138.1.177.in-addr.arpa. IN PTR ns2.shackvirtual.com.br.

40.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.45 40.40-47.138.1.177.in-addr.arpa. IN PTR ns1.shackvirtual.com.br. 41.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.46 41.40-47.138.1.177.in-addr.arpa. IN PTR ns2.shackvirtual.com.br.

still have doubts as to configure the machine's cloudmin or virtual machine. Could you tell me

I configured a virtual machine with only the ips and it looked like this:

$ ttl 38400

138.1.177.in-addr.arpa. IN SOA shackvirt.cloudmin.tchod.com. guimaraesphp.hotmail.com. ( 1353599082

10800

3600

604800

38400)

138.1.177.in-addr.arpa. IN NS shackvirt.cloudmin.tchod.com.

45.138.1.177.in-addr.arpa. IN PTR ns1.shackvirtual.com.br.

46.138.1.177.in-addr.arpa. IN PTR ns2.shackvirtual.com.br.

45.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.45

45.40-47.138.1.177.in-addr.arpa. IN PTR ns1.shackvirtual.com.br

46.40-47.138.1.177.in-addr.arpa. IN A 177.1.138.46

46.40-47.138.1.177.in-addr.arpa. IN PTR ns2.shackvirtual.com.br

Half solve the problem

Now when I do the test I get this message:

TECHNICAL REQUIREMENTS FOR ELECTRONIC MAIL DELIVERY - TEST DNS

1) Checking the reverse DNS of the IP [177.1.138.45]:

$ Host 177.1.138.45

45.40-47.138.1.177.in-addr.arpa domain name pointer ns1.shackvirtual.com.br.138.1.177.in-addr.arpa.

Result: OK, the IP [177.1.138.45] resolves to a valid host [ns1.shackvirtual.com.br.138.1.177.in-addr.arpa.].

2) Checking the DNS host direct [ns1.shackvirtual.com.br.138.1.177.in-addr.arpa.]:

$ Host ns1.shackvirtual.com.br.138.1.177.in-addr.arpa.

Host ns1.shackvirtual.com.br.138.1.177.in-addr.arpa. not found: 3 (NXDOMAIN)

Result: ERROR, the host [ns1.shackvirtual.com.br.138.1.177.in-addr.arpa.] Does not resolve to the IP [177.1.138.45].

TECHNICAL REQUIREMENTS FOR ELECTRONIC MAIL DELIVERY - TEST DNS

1) Checking the reverse DNS of the IP [177.1.138.45]: $ Host 177.1.138.45 45.40-47.138.1.177.in-addr.arpa domain name pointer ns1.shackvirtual.com.br.

Result: OK, the IP [177.1.138.45] resolves to a valid host [ns1.shackvirtual.com.br.].

2) Checking the DNS host direct [ns1.shackvirtual.com.br.]: $ Host ns1.shackvirtual.com.br. ns1.shackvirtual.com.br has address 177.1.138.45

Result: OK, the host [ns1.shackvirtual.com.br.] Resolves to its IP [177.1.138.45].

The DNS IP [177.1.138.45] is correctly configured

however...

TECHNICAL REQUIREMENTS FOR ELECTRONIC MAIL DELIVERY - TEST DNS

1) Checking the reverse DNS of the IP [177.1.138.46]: $ Host 177.1.138.46 46.40-47.138.1.177.in-addr.arpa domain name pointer ns2.shackvirtual.com.br.138.1.177.in-addr.arpa.

Result: OK, the IP [177.1.138.46] resolves to a valid host [ns2.shackvirtual.com.br.138.1.177.in-addr.arpa.].

2) Checking the DNS host direct [ns2.shackvirtual.com.br.138.1.177.in-addr.arpa.]: $ Host ns2.shackvirtual.com.br.138.1.177.in-addr.arpa. Host ns2.shackvirtual.com.br.138.1.177.in-addr.arpa. not found: 3 (NXDOMAIN)

Result: ERROR, the host [ns2.shackvirtual.com.br.138.1.177.in-addr.arpa.] Does not resolve to the IP [177.1.138.46].

The DNS IP [177.1.138.46] is not configured correctly

I believe we should take time to propagate

Yes, wait a bit for DNS propagation .. from what I can see, 177.1.138.45 and 177.1.138.46 reverse and forward resolve correctly.

Worked perfectly, thank virtualmin staff and especially the "Locutus" that contributes decisively in this solution.

TECHNICAL REQUIREMENTS FOR ELECTRONIC MAIL DELIVERY - TEST DNS

1) Checking the reverse DNS of the IP [177.1.138.46]: $ Host 177.1.138.46 46.40-47.138.1.177.in-addr.arpa domain name pointer ns2.shackvirtual.com.br.

Result: OK, the IP [177.1.138.46] resolves to a valid host [ns2.shackvirtual.com.br.].

2) Checking the DNS host direct [ns2.shackvirtual.com.br.]: $ Host ns2.shackvirtual.com.br. ns2.shackvirtual.com.br has address 177.1.138.46

Result: OK, the host [ns2.shackvirtual.com.br.] Resolves to its IP [177.1.138.46].

The DNS IP [177.1.138.46] is correctly configured

1) Checking the reverse DNS of the IP [177.1.138.45]: $ Host 177.1.138.45 45.40-47.138.1.177.in-addr.arpa domain name pointer ns1.shackvirtual.com.br.

Result: OK, the IP [177.1.138.45] resolves to a valid host [ns1.shackvirtual.com.br.].

2) Checking the DNS host direct [ns1.shackvirtual.com.br.]: $ Host ns1.shackvirtual.com.br. ns1.shackvirtual.com.br has address 177.1.138.45

Result: OK, the host [ns1.shackvirtual.com.br.] Resolves to its IP [177.1.138.45].

The DNS IP [177.1.138.45] is correctly configured