Questions tagged [domain-name-system]

The Domain Name System, usually referred to by the acronym DNS, is a hierarchical, distributed database where the keys are domain names. Questions involving publicly accessible domains should include the real, Fully Qualified Domain Name (FQDN)

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Postfix - MX: Host not found error but dig and nslookup are OK

I had a working Postfix email server on Centos 7 when I decided to reconfigure my host networking (IP addressing, DNS, etc.), after reconfiguration, mail sending is no longer working. /var/log/...
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1answer
15 views

Does a reverse proxy use subdomains to know which private IP to route to?

I know this is very basic, but I'm very new to the reverse proxy, network admin world. Could someone provide a high level overview how a reverse proxy knows which server/port to route traffic to? Does ...
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2answers
35 views

is it possible to host multiple server that have different IPs on the same port such as 80?

I am trying to setup multiple website domains, but from different servers and because they are different servers they have different IPs, I am wondering if I could port forward each domain to 80, so ...
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0answers
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Turned DNSSEC off then on again. Now I can't send emails. Why?

While testing out a new email provider, I turned off DNSSEC for my domain, changed MX records and switched to Google's name servers and removed my old name servers. The realizing I didn't have to turn ...
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24 views

host command resolves IP address but gives host not found error

I am having issues with one of the EC2 instance where I have application dying because it is not able to resolve other systems in the same VPC. When I run host ip-10.123.22.100 command on a server, I ...
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8 views

DNS records of unexpected NIC IP addresses are created when Realm with Winbind joins a client to Active Directory

I created two machines: Windows Server 2016 with Active Directory and DNS server CentOS 7 client with two (or more) NICs that each be connected to different networks. The Win server is connected to ...
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1answer
14 views

Email FROM header authentication using subdomain delegation

Our company owns the domain somecompany.com and uses an external email provider emailemailprovider.com to send emails. The email provider recommends to delegate a subdomain for them to automatically ...
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25 views

Windows server 2008 DNS Server

Our security team reported that our DNS server holding our domain, is sometime querying the hostnames from public resolvers while not omitting its own domain name from the query. Like this: _ldap._tcp....
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1answer
21 views

A record via multiple CNAME record [closed]

At my home I have several services that are reachable from outside my home (http, ssh, plex, etc). To manage it easily I created a A-record in my DNS for everything that is hardware (computers, ...
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1answer
70 views

DNS propagation taking over two months

Two months ago I registered bunch of expired domains and set new nameservers to them just like I've done before. Never had any issues. For some reason the DNS propagation never finished with these ...
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1answer
71 views

SRV Record not working GoDaddy HTTPS on separate port

I'm having trouble setting up an office with one public IP and multiple web services running on separate ports. One of the services is a media server and I'm trying to add an SRV record to godaddy in ...
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1answer
24 views

using different domain for static contents?

Say my web server is named example.com now I want to use cloudflare cdn for media.example.com . but cloudflare requires to change example.com 's name server to cloudflare's, and I can't do that I ...
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4answers
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EC2 How to use private ip when using domain name?

I read you incur cost if one of your ec2 accesses another ec2 with public ip (going through internet) You can avoid that cost by using private ip. So I want them to use private ip. Furthermore, I ...
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745 views

How to measure and optimize DNS influence on CDN performance?

I want to measure and optimize the DNS & TSL costs on CDN performance. A) Setup Mobile app requests file at URL https://file.mydomain.site/file.jpg Provider A has a CNAME entry for file.mydomain....
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1answer
110 views

Why does it not work when I set CNAME to let my domain point to another domain?

I have registered a domain, say myDomain.com, and I want to try out how CNAME works. I changed the CNAME of www.mydomain.com in GoDaddy and let it point to another domain, say Amazon.com, but when I ...
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Advice on DNS good practice for LAN and public queries with DNSDist / recursor / powerdns

I am setting up a cluster of DNS that are soon going to reply to both LAN clients and public internet queries. On the internet is a special network (XX.YY.ZZ.AA/26) that I need to reply differently ...
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1answer
30 views

Internal DNS issue

Our internal network has been setup with the same domain as our external website. We currently point a www record at the server IP (acquia) - this works but means we don’t get cloudflare’s ...
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1answer
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AWS alb and DNS routing

I have example.com behind ALB Since I'm using external DNS service other than route53, I created a CNAME in my DNS service such as some-unique-name.ap-northeast-2.elb.amazonaws.com pointing to ...
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3answers
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Nameserver not resolving for all locations

I have a problem with a domain name not resolving the nameservers correctly. I am not sure where else I can ask for help. I have spent a total of about 5 hours on support line chat or on the phone ...
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0answers
44 views

Finding a hostname in DNS by partial match [closed]

I can't remember an internet hostname that I use very infrequently. I know that the hostname contains the substring "aware". The hostname might have been mico-aware, microaware, mcaware, etc. Is ...
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1answer
36 views

How can I block Docker from trying to resolve external DNS names?

I'm setting up a Docker container without internet access and it's slow. The container seems to try make DNS lookups which are bound to fail and only time out slowly. sudo docker network create --...
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0answers
78 views

No Domain Controller found when joining a Windows 10 client to a OpenLDAP+Kerberos+SambaDC (SUSE 12SP4)

I'm afraid I need some help. I've setted up a OpenLDAP + Kerberos authentication server that works flawlessly in a Linux environment. Linux Clients join to it without any problem and I'm able to login ...
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1answer
28 views

Internal DNS Setup [Bind9] , unable to dig from another machine, but able to dig locally

I have a local network with 3 machines, each one of them is able to ping the others. I have setup a DNS server using bind9 in one of those machines, and asigned the ftp.rp.iesdomain to one of its ip. ...
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1answer
77 views

Nginx analyze CNAME chain

let say I have DNS setup in a way that: www.test.com points with CNAME to test.my-main-platform.com and test.my-main-platform.com point to server where we have Nginx. www.test.com --> test.my-...
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1answer
62 views

BIND Zone Transfer with two views

I have a simple lab/testing Master/Slave configuration (showed below) and I would like to transfer both views to the slave. Unfortunately after the zone transfer both views in slave have records from ...
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1answer
33 views

How can I change the A record for my DNS while redirecting users from old IP to the new IP?

I have a DNS record that points to ipA (A record). I want to change the record to ipB, however I cannot accept anything on ipA as soon as ipB is in use, because the application can't exist in two ...
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1answer
33 views

Dns resolution [BIND9] , pinging to the right domain, but answer coming from another domain

I have created my /etc/network/interfacesconfigured like this: /etc/network/interfaces Then I have 2 files i created in /etc/bind One of them is db.rag.es , which looks like this: db.rag.es file And ...
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1answer
69 views

How to make 'redirected webpage' accesible inside LAN?

We have our company's website https://www.website1.com that is hosted on HostGator and that was inaccessible only from the inside LAN. I added a new Host A record in DNS for www which points to the ...
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1answer
78 views

Intermittent DNS failures [closed]

We have intermittent DNS failures. Upon troubleshooting we found from our server, (where the domain is pointed to) gives connection timeout when queried against few TLD ns. Ex: dig domain @tldns (...
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25 views

Downside to using *.herokuapp.com domain?

I need to point thousands of TLDs to the same Rails app hosted in Heroku. So far I have automated the process of adding domains to CloudFlare and Heroku, but SSL has proven to be a challenge. Heroku ...
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17 views

Static Name Server Azure DNS

I want to host DNS zones for multiple domain names in my Azure environment. The creation of domain names is automated, they are created in Plesk and with a plugin they are created in Azure. For every ...
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3answers
51 views

Is it possible to point your domain to a website and still keep emails on the old domain provider? [closed]

I have been struggling with an issue for a long time. I have bought a domain from mauritiusbiz. I made a website on wix.com When I wanted to connect my website to my domain, the Wix support pointed ...
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Linking Go Daddy Domain to OVH Server

So, I've tried linking my domain to my OVH server. Firstly, I added my domain name, via multi-site to OVH, it gave me my A & my TXT values, which I had previously already linked to my domain ...
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client not logged to local domain controller

I have a setup of Active Directory 1 DC with 4 RODCs A is my main DC. B,C,D,E are RODCs in different Branches. But When I checked from client pc the "logon server" is showing different location DC....
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1answer
40 views

CAA issuewild multi-level sub-sub-domains

CAA probably makes sure that issued certificates come from my CA and not from another one. Given in the DNS: example.com. 300 IN CAA 0 issue "ca.example.com" example.com. 300 IN CAA 0 issuewild "ca....
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0answers
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DNS CNAME lookup fail once in a while

I've created the following CNAME record: Name:selector1._domainkey.damvig.com Value: selector1-damvig-com._domainkey.damvig.onmicrosoft.com (It has no A record, but a TXT) The CNAME record is created ...
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2answers
85 views

Why MX record is not updating the correct A record

I've notice about cache in the ISP's but i wish know more about this and how to deal with that. I have more of 24 hours waiting my MX record update to the correct IP. Look this: I have an 5 priority ...
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1answer
70 views

How to properly set-up ou DNS Zone delegation for the “_acme-challenge” subdomain?

We have hard times setting up a DNS Zone Delegation for one of our subdomains. We have one DNS record "_acme-challenge" that will change frequently, and this DNS record is defined directly on our ...
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2answers
50 views

Setting up a subdomain to a distinct server

I am setting up a subdomain on Google Domains in the form subdomain.mydomain.com, so that this URL lead users to my server (AWS EC2 instance). In Google Domains I can configure subdoamins with ...
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1answer
28 views

Control A-records for multiple sites in 1 place

Hopefully this makes sense.. We have multiple servers hosting a couple of hundred web sites. All domain names are controlled mainly by clients and pointed to 1 of our servers using A-Records. We ...
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3answers
6k views

Why domain return different public ip when do a Ping

I have a domain that is not working because of DNS. I checked it in https://dnschecker.org/ and https://who.is Both sites return the correct IP server, but my domain it's not working. When I do it a ...
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1answer
27 views

Automatically append “-bar” to foo to resolve foo as foo-bar.baz.com?

In Linux (Ubuntu 18.04 and RHEL) my /etc/resolv.conf says: nameserver 192.168.0.1 search baz.com And I get this: getent hosts www 192.168.0.2 www.baz.com But I'd like to do this: getent hosts foo ...
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0answers
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How can I configure Unbound to use Microsoft Virtual Adapter

I need a lightweight DNS and I found Unbound. It works fine with a wired ethernet adapter, but I need that it work with a WiFi adapter (to resolve queries from wireless devices). I use a program to ...
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2answers
397 views

Hide subdomains from scan tools

How can I hide the subdomains list from scan tools like dnsdumpster? I have some subdomains, where I keep dev versions of my projects. I need to be sure that nobody can know about subdomains.
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1answer
21 views

How to trust another Nameserver/Zone specificly?

For making sure a resolver is also able to resolve when not connected to the internet (which is usually not the case), I have configured a forward zone: zone "example.com" { type forward; ...
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2answers
198 views

Access cloud machines by name

I have production machines on Google Cloud and Amazon. On both clouds, I have common server on each called monitoring which has public ip. Through these monitoring machines, I access all machines on ...
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0answers
34 views

DNS server scavenges active records

I have 3 DNS servers and one of them removes too many records including active ones. Last time 412 records (out of 2086 if I get it right) were removed: The DNS server has completed a scavenging ...
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1answer
38 views

How is truncation performed in DNS according to RFC 1035?

I'm trying to implement my own DNS server from scratch. However, I'm having difficulty understanding how RFC 1035 recommends truncation to be performed. Section 6.2 says: When a response is so ...
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0answers
22 views

Using DNS to redirect domain to another website but keep subdomains working (Google Domains)

We're using Google Domains and have a domain we want to redirect to another domain, but we have subdomains that we want to remain in tact. Using Website Forwarding results in the subdomains not ...
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1answer
28 views

Use IPv6 from MAC for DNS?

I am running a private cloud server and I am facing the problem that my DNS provider does not support dynamic update of the IPv6 address. I know that every IPv6 device has a 'default' IPv6 address ...