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before I begin kindly note that I am a newbie and still learning.
Yesterday 10 hours from now, I had to move all my hosted websites to a new server(to be more specific - from one droplet to a new droplet). So, since the websites were moved to a new server, meant that their ip addresses would change too. So, I updated the dns configuration for all the websites to point to the new ip address now. But I was unaware that the previous dns configuration had set the ttl to 86400(1 day). I learned about this concept after searching on google why my websites would still resolve to the old server.
So, that basically meant that the old dns config is cached for 1 day and I have to wait that long to see the change in the domain name resolution to reflect the websites from the new server.
So, i tried to perform nslookup and dig commands on the domains to just check the remaining ttl. But, this is where I am upset right now.
The nslookup command with -debug parameter gave the following result:
Please Note:- I have replaced my website's domain name with (mywebsite.com) and my new server's ip address with (new.server.ip.address) from the actual nslookup result
nslookup -debug mywebsite.com new.server.ip.address
------------
Got answer:
HEADER:
opcode = QUERY, id = 1, rcode = REFUSED
header flags: response, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0
QUESTIONS:
address.ip.server.new.in-addr.arpa, type = PTR, class = IN
------------
Server: UnKnown
Address: new.server.ip.address
------------
Got answer:
HEADER:
opcode = QUERY, id = 2, rcode = NOERROR
header flags: response, auth. answer, want recursion
questions = 1, answers = 1, authority records = 2, additional = 2
QUESTIONS:
mywebsite.com, type = A, class = IN
ANSWERS:
-> mywebsite.com
internet address = new.server.ip.address
ttl = 14400 (4 hours)
AUTHORITY RECORDS:
-> mywebsite.com
nameserver = ns2.centos-webpanel.com
ttl = 86400 (1 day)
-> mywebsite.com
nameserver = ns1.centos-webpanel.com
ttl = 86400 (1 day)
ADDITIONAL RECORDS:
-> ns1.centos-webpanel.com
internet address = 127.0.0.1
ttl = 14400 (4 hours)
-> ns2.centos-webpanel.com
internet address = 127.0.0.1
ttl = 14400 (4 hours)
------------
------------
Got answer:
HEADER:
opcode = QUERY, id = 3, rcode = NOERROR
header flags: response, auth. answer, want recursion
questions = 1, answers = 0, authority records = 1, additional = 0
QUESTIONS:
mywebsite.com, type = AAAA, class = IN
AUTHORITY RECORDS:
-> mywebsite.com
ttl = 86400 (1 day)
primary name server = ns1.centos-webpanel.com
responsible mail addr = myemail#gmail.com
serial = 2013071601
refresh = 86400 (1 day)
retry = 7200 (2 hours)
expire = 3600000 (41 days 16 hours)
default TTL = 86400 (1 day)
------------
Name: mywebsite.com
Address: new.server.ip.address
Now, here's what upset me. As in the above result, the ttl (even after 10 hours since changing the dns configuration) shows 86400. I was expecting it to show the remaining ttl but the ttl is constant at 86400. Does that mean that the dns will never update for my websites?? The ttl just does not decrease.
So, to verify even further I tried using linux's dig command and here's the result I got.
Please Note:- I have replaced my website's domain name with (mywebsite.com) and my old server's ip address with (old.server.ip.address) from the actual dig result
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6_9.5 <<>> mywebsite.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15423
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;mywebsite.com. IN A
;; ANSWER SECTION:
mywebsite.com. 83221 IN A old.server.ip.address
;; Query time: 0 msec
;; SERVER: 67.207.67.2#53(67.207.67.2)
;; WHEN: Mon Feb 5 01:55:05 2018
;; MSG SIZE rcvd: 44
Now here, the dig command resolves the domain to my old server's ip address and it shows the ttl as 83221 !!! Like I said, its more than 10 hours that I updated the dns configuration to point to my new server's ip address. But, even after 10 hours passing, the ttl says 83221 !!!!
Running the dig command again does reflect a reduction in the ttl here though, unlike the nslookup command.
So, what do you guys think is the problem that has been going on here?? Or I am misunderstanding something?? If so, please correct me. Any kind of help will seriously assist a lot. It would really help me if someone can explain what is going on here and also what's wrong or if something is wrong with my new server.
And just if it helps, I have kept the websites' files on both - the old server as well as the new server.
Thanks.
Edit:- (Solved)
So here's what fixed all the issues I was facing. I use centos web panel on my server which comes bundled with freedns manager. So, a bug in freedns kept my nameservers and domains' dns from updating. So, I went for cloudflare dns and that fixed all the issues.
Your domain is not correctly configured, please use online diagnostics tools such as dnsviz.net, see the report: http://dnsviz.net/d/mkinfra.in/dnssec/
You are in a lame delegation situation.
If we query .IN authoritative nameservers for your domain, they reply:
mkinfra.in. 86400 IN NS ns1.centos-webpanel.com.
mkinfra.in. 86400 IN NS ns2.centos-webpanel.com.
mkinfra.in. 86400 IN NS ns3.centos-webpanel.com.
mkinfra.in. 86400 IN NS ns4.centos-webpanel.com.
mkinfra.in. 86400 IN NS ns5.centos-webpanel.com.
If we query any of these 5 nameservers for your domain, they reply:
mkinfra.in. 86400 IN NS ns1.centos-webpanel.com.
mkinfra.in. 86400 IN NS ns2.centos-webpanel.com.
Which is not the same set of records. You will first need to resolve this discrepancy.
For your website they all reply the same:
www.mkinfra.in. 86400 IN CNAME mkinfra.in.
mkinfra.in. 86400 IN A 139.59.63.210
So they all reply will your old IP and not the new one. Your problem has nothing to do with TTLs: the authoritative nameservers for your domain are still not delivering the new IP address you wish, so you have to configure them properly. If you do it yourself, please remember to update the serial of the zone for any change.
The serial is in fact 2018012401 which follows the pattern YYYYMMDDXX so we can infer that the zone was changed on January 24th but not since then (or was changed but serial not updated so the new content is not taken into account at all).
And to reply to your other question: if you query an authoritative nameserver you will always get the same TTL, which is per design. It is only if you query a resolving and caching nameserver that you will see the TTL decreasing from one query to another, because the case is slowly forgetting about the data it resolved in the past.
Never use nslookup but always dig but always specify the command you use when you ask for people to check what you are doing (it is very important to specify the nameserver you query with the # parameter of dig since the results will be vastly different from an authoritative or a recursive nameserver).
Puzzling problem sending emails from one server to another.
Sending from Server-01 pr#example.camp TO Server-02 eman#example.edu.au
Server 02 bounces with sender verify fail for <pr#example.camp>: Unrouteable address
On Server-02 running dig MX example.camp resolves fine with:
;; ANSWER SECTION:
mus.camp. 2869 IN MX 10 server01-aus.emanwebdesign.com.
mus.camp. 2869 IN MX 0 server01-aus.emanwebdesign.com.
;; AUTHORITY SECTION:
mus.camp. 2869 IN NS ns10.domaincontrol.com.
mus.camp. 2869 IN NS ns09.domaincontrol.com.
Also from Server-02 I can telnet into port 25 of mus.camp and verify the existence of the email address (pr#...).
Any clues as to why Exim's sender verify is failing?
Edit
exim -bvs pr#example.camp returns
pr#example.camp failed to verify: Unrouteable address
Worked out the problem was that the mus.camp domain was originally hosted on Server-02 but then moved to Server-01. Server-02 however was still trying to lookup the email address within itself instead of going to Server-01.
To solve the problem I deleted the mail and dns records from Server-02. (using VestaCP).
As i am trying to open my site(posting.ly) but its not working rather it shows blank page for a while than error of "could not load posting.ly"
I have updated the namespace and tested it,updated A recoord,but cannot figure out the problem.I have already worked with DNS and i know this should work plus its more than 24 hrs so this should work or show me a proper error.
Hosting is rackspace and i have added A record of the ip address.
This appears to be fine now. No www or wildcard, but main domain resolves.
$ checksoa posting.ly
Serial # RTT(ms) Nameservers (name, IP, SOA mname field) for posting.ly
1403808455 50 dns1.stabletransit.com 69.20.95.4 SOA: ns.rackspace.com
1403808455 80 dns2.stabletransit.com 65.61.188.4 SOA: ns.rackspace.com
$ dig +noall +answer +authority posting.ly
posting.ly. 300 IN A 162.13.143.172
$ dig +noall +answer +authority www.posting.ly
posting.ly. 300 IN SOA ns.rackspace.com. azm.dar.gmail.com. 1403808455 21600 3600 1814400 300
I develop our application and can succeed to get hotsname through func: ServiceFound(DNSSDService sref, DNSSDFlags flags, uint ifIndex, String serviceName, String regType, String domain)
I checked the wireshark and Log, the serviceName is right.
My question:
Why I can not ping it through "serviceName.domain", e.g: ping serviceName.local. (I want to use ping to test the network available beofre run my application. now it is blocked the failed ping)
But I can ping it through the real IP, e.g: ping 1.2.3.4 (This means that the network is ok)
ServiceFound and ServiceResolved only provide serviceName.
So how to solve this problem:
1) one simple way to get IP
or 2) how to solve the problem of "ping serviceName.local"
Thanks a lot for your support in advance!
************************Update*******
I retest it on other PC:
I use dns-sd.exe to debug the network
Using following command can get servicename
$ dns-sd.exe -B _http._tcp
Browsing for _http._tcp
Timestamp A/R Flags if Domain Service Type Instance Name
4:33:52.663 Add 3 3 local. _http._tcp. test
Using following command can get zone file
$ dns-sd.exe -Z _http._tcp
Browsing for _http._tcp
_http._tcp PTR Officejet\032Pro\032L7500\032[FEDCE8]._http._tcp
Officejet\032Pro\032L7500\032[FEDCE8]._http._tcp SRV 0 0 80 HPFEDCE8.local. ; Replace with unicast FQDN of target host
Officejet\032Pro\032L7500\032[FEDCE8]._http._tcp TXT ""
using following command can get IP (based on HPFEDCE8.local. in above feedback)
$ dns-sd.exe -G v4 HPFEDCE8.local.
Timestamp A/R Flags if Hostname Address TTL
4:43:38.965 Add 2 3 bej1301Dell2360.local. 10.61.20.99 240
So I can ping it through HPFEDCE8.local.
But in my Test PC: "$ dns-sd.exe -B _http._tcp" is ok, but others commands are failed.
So I think this is the root cause.
So my question is:
as I know, we can use "instance Name" to generate the hostname: test.local.
why they are different from "HPFEDCE8.local." in the zone file
why "ping HPFEDCE8.local." ok and "ping test.local." failed
Do you have any others ideas for my Test PC?
Thanks a lot!!
How do I programatically determine the WHOIS server for a given TLD?
For name servers, I just query a.root-servers.net
Is there an equivalent procedure for WHOIS?
I know "host -t ns xxx." yields the DNS for a TLD: can the WHOIS
server be derived from that result?
It's in the SRV-record _nicname._tcp.tld -
For example;
# dig +short SRV _nicname._tcp.no
0 0 43 whois.norid.no.
More information can be found in the Wikipedia-article of whois.
That works for some tld's at least - but not .com.
tld.whois-servers.net is a commonly used alias that should point to a valid whois-server. For example com.whois-servers.net