I'm setting up and internal domain, so far portions of the DNS appear to be working however, when I try to ping the domain i.e.: ping cscd.internel I get the following response:

[louis@Lenovo-T510 ~]$ nslookup cscd.internel
;; Got SERVFAIL reply from 10.7.30.20, trying next server
;; Got SERVFAIL reply from 10.7.30.20, trying next server
Server: 208.67.220.220
Address: 208.67.220.220#53

** server can't find cscd.internel: NXDOMAIN

I get the same response when I also do an nslookup cscd.internel.

I have reverse DNS configured with 30.7.10.in-addr-arpa zone that contains the following entry: 25.30.7.10.in-addr-arpa PTR 86400 cscd.internel.

It appears to me that nslookup and ping are looking outside for the resolution. I have and internal resolution so why would it be looking outside? What am I missing?

Thanks

From the above nslookup output, looks like your server at 10.7.30.20 gives a SERVFAIL, so the next nameserver is used (opendns: 208.67.220.220) that of course gives a NXDOMAIN answer.

You should post here your dns server config file and the zone file, both included in CODE tags for readability, so we could try to help you.


Regards

OK Please see below:

Zone ID: cscd.internel
Domain Name:cscd.internel
Type:master
Status:enabled

Name Type TTL Information

CSCD-NAS-1.cscd.internel. A 86400 10.7.30.25
CSCD-NAS-1.cscd.internel. CNAME 86400 mailserver.cscd.internel.
cscd.internel. MX 86400 10 mailserver.cscd.internel.
cscd.internel. NS 86400 ns.cscd.internel.
mailserver.cscd.internel. A 86400 10.7.30.25
ns.cscd.internel. A 86400 10.7.30.20

Zone ID: 30.7.10.in-addr.arpa
Domain Name:30.7.10.in-addr.arpa
Type:master
Status:enabled

Name Type TTL Information

25.30.7.10.in-addr.arpa. NS 86400 ns.
25.30.7.10.in-addr.arpa. PTR 86400 cscd.internel.
25.30.7.10.in-addr.arpa. PTR 86400 mailserver.
30.7.10.in-addr.arpa NS 86400 ns.

So what did I do wrong?

What is the nameserver software you're running?
Because the zone file quite unusual.

Can you resolve the ns.cscd.internel IP address from the nameserver itself?

Yes I Can please see below:

louis@Lenovo-T510 ~]$ dig ns.cscd.internel @10.7.30.20

; <<>> DiG 9.9.4-RedHat-9.9.4-72.el7 <<>> ns.cscd.internel @10.7.30.20
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 25339
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;ns.cscd.internel. IN A

;; Query time: 13 msec
;; SERVER: 10.7.30.20#53(10.7.30.20)
;; WHEN: Tue Jul 02 14:51:54 EDT 2019
;; MSG SIZE rcvd: 45

I'm using DNS on a Synology NAS, they've not been very helpful all so I'm working to resolve it on my own. What did you find strange?

Thanks

Sorry for the error my DNS is on a Synology 2600Ac Router.

Thanks

Getting a SERVFAIL means that there is a misconfiguration somewhere, most likely in the zone file.
The only error I see for now, is that you have both an A and a CNAME record for CSCD-NAS-1.cscd.internel. Delete the latter and see if it helps.

BTW I find strange the zone file format (TTL after RR type for example), but I guess you've posted the contents of the dns config web interface.
If you can export the zone file to the classic format, it could be more useful.

For the heck of it, could you try:

The nslookup displayed the following:

[louis@Lenovo-T510 ~]$ nslookup 10.30.20
;; Got SERVFAIL reply from 10.7.30.20, trying next server
Server: 208.67.220.220
Address: 208.67.220.220#53

** server can't find 10.30.20: NXDOMAIN

Any export of the zone file:

$ORIGIN cscd.internel.
$TTL 86400
cscd.internel. IN SOA ns.cscd.internel. louis.cscd.internel. (
2019061904
43200
180
1209600
10800
)
CSCD-NAS-1.cscd.internel. 86400 CNAME mailserver.cscd.internel.
cscd.internel. 86400 MX 10 mailserver.cscd.internel.
mailserver.cscd.internel. 86400 A 10.7.30.25
CSCD-NAS-1.cscd.internel. 86400 A 10.7.30.25
cscd.internel. NS ns.cscd.internel.
ns.cscd.internel. 86400 A 10.7.30.20

Export of Reverse zone file:

$ORIGIN 30.7.10.in-addr.arpa.
$TTL 86400
30.7.10.in-addr.arpa. IN SOA ns.30.7.10.in-addr.arpa. louis.30.7.10.in-addr.arpa. (
2019070103
43200
180
1209600
10800
)
25.30.7.10.in-addr.arpa. 86400 NS ns.
25.30.7.10.in-addr.arpa. 86400 PTR cscd.internel.
25.30.7.10.in-addr.arpa. 86400 PTR mailserver.
30.7.10.in-addr.arpa. 86400 NS ns.

The CNAME record type points to the mail server, if I remove the CNAME will I still be able to connect the mail server?

Thanks

OP. PLEASE use code tags when posting output. Your posts are very hard to read without them.
See this

That's probably the cause of the confusion about the CNAME record...

I usually set up the mail.domain.com with an A record rather than a CNAME record. I don't know if that makes a difference.

OH! You have both a CNAME and an A record for mailserver.cscd.internel That's what bathory is talking about. Try removing the CNAME record.
Although your posts of your configuration are hard to read, I do not see an A record for cscd.internel, either.

I removed the CNAME record and got the following results:

[louis@Lenovo-T510 ~]$ nslookup 10.7.30.20
Server: 10.7.30.20
Address: 10.7.30.20#53

** server can't find 20.30.7.10.in-addr.arpa.: NXDOMAIN

The above suggest that there is no reverse lookup for the IP Address, I checked the above reference and there is no reverse entry for the IP Address 10.7.30.20. Therefore one should be added, should it be a PTR record or NS record because it is the start of the domain?

Thanks

After removing the CNAME record, does the
work now?
If not, what happens?

(Let’s focus on the original question first.)

Here are the results of nslookup cscd.internel:

[louis@Lenovo-T510 ~]$ nslookup cscd.internel
Server: 10.7.30.20
Address: 10.7.30.20#53

*** Can't find cscd.internel: No answer

OK. You've fixed the SERVFAIL problem! Good...bathory was right about the CNAME and A issue.

Now, we're at what I said earlier...there is no A record defined for cscd.internel in the config you posted
There are A records for:
mailserver.cscd.internel
ns.cscd.internel
and
CSCD-NAS-1.cscd.internel
...but none for cscd.internel

a should work just fine.
Try it. Let us know.
Use [code] tags when you post your output. Please.

it did work and so did the ping, please see below:

[louis@Lenovo-T510 ~]$ nslookup CSCD-NAS-1.cscd.internel
Server: 10.7.30.20
Address: 10.7.30.20#53

Name: CSCD-NAS-1.cscd.internel
Address: 10.7.30.25

[louis@Lenovo-T510 ~]$ ping CSCD-NAS-1.cscd.internel
PING CSCD-NAS-1.cscd.internel (10.7.30.25) 56(84) bytes of data.
64 bytes from 10.7.30.25 (10.7.30.25): icmp_seq=1 ttl=64 time=9.62 ms
64 bytes from 10.7.30.25 (10.7.30.25): icmp_seq=2 ttl=64 time=8.18 ms
64 bytes from 10.7.30.25 (10.7.30.25): icmp_seq=3 ttl=64 time=8.24 ms
64 bytes from 10.7.30.25 (10.7.30.25): icmp_seq=4 ttl=64 time=7.81 ms

Should I do anything else to cover my bases?

Thanks so much for your help.