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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Google Cloud DNS giving 404 on top level domain

I'm using Google Cloud DNS and Google App Engine Standard to configure an application. Currently, I configured the DNS like this mydomain.com. A 300 216.239.32.21 216.239.34.21 216.239.36.21 ...
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DNS Configuration for Web Server and Mail Server

I am new to computer networking. I have successfully added MX record of email service provider (Yandex), and it works finely. Also I added A record pointing to the Web Server which installed on VPS. ...
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How to properly set up BIND as DNS cache service?

I have installed BIND9 on my Debian Stretch virtual machine, it's part of my virtual networking lab - I want machine with BIND installed to act as firewall, nat, dns and dhcp for others(for now I set ...
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DNS doesn't seem to work for Domain Controller

I took over this small windows network from another admin who is no longer involved. It's a simple setup, one bare metal server with Windows 2016 as a DC and fileserver, all in one. With less than 10 ...
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53 views

Firewall rules for accessing Google-Cloud-Storage from the outside world

I'm deploying an application that relies on GCS at a customer's site. The customer's firewall allows whitelisting domains for outgoing connections, so I've whitelisted the known GCS domains (storage....
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DNS not resolve after DNS Amplification Attack

I have a VPS that runs number of small sites. It runs over 5 years without any problem. Last night I notified 12K GB outgoing traffic and I researched about that and it seems it was an DNS ...
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26 views

Properly configuring recursive dns

We have an internal intranet that we'd like to be hierarchical in nature, something like: internal.example.com (ns at ns1.internal.example.com) clientA.internal.example.com (ns at ns1.clientA....
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27 views

DNS Zone config with Centos Web Panel doesnt work [closed]

I have been trying for hours now to setup my domain with the CentOS Web Panel and own nameservers. I did change the nameserver at the domain registrar and entered the IP values for these nameservers, ...
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dns NXDOMAIN error with external view

we are trying to configure a bind9 server. We have two different views, one for the internal zone (dmz) and another for external users who want to access to the dmz web. The problem is that we may be ...
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Manually edit records on Slave DNS

Scenario: Primary DNS BIND server is down. I need to edit a DNS record on the slave server from IP address from x.x.x.1 to x.x.x.2 I go to my zone file, increase the serial number, edit the record,...
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2answers
57 views

Https version of web application is not working but http is?

I am using Heroku to host which provides me a nice https: address: https://some_random_string.herokuapp.com/ I use Namecheap to setup my DNS and I do this using: CNAME Record | www | www.my_domain....
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1answer
33 views

DNS NSLOOKUP server failed for MX entry

For various reasons I won't go into I've set up a custom DNS server for a delegated subdomain of my main domain. This DNS server is a .NET application which uses the ARSoft DNS library to respond to ...
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71 views

Internal DNS TTLs

Four-site company using Windows Domain and DNS servers. Minimum of one DC/DNS server per site. One site is HQ and hosts most companywide servers and services. DNS records for Windows servers are ...
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Prevent “hostmaster” subdomain from redirecting to the main site

I host mainsite.com and othersite.net on a single Debian 8 server with nginx/1.6.2. Recently I discovered that Google indexed hostmaster.othersite.net and this subdomain shows full content of mainsite....
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1answer
39 views

Using an Elastic Load Balancer without Route53

We have setup an Elastic Beanstalk environment that spins up EC2 instances and adds a classic load balancer in front of them. Typically, you would set your DNS to Route53's name servers and then use ...
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29 views

Subdomain that uses Route 53 without migrating parent domain

I currently have a domain (asoba.co) that is hosted on Linode, and for which I use Linode nameservers. This site currently works as expected. My goal is to have an additional subdomain for a webapp ...
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38 views

Redirecting my existing NS records to Cloudflare NS

I run a domain parking service, let's call it domainparking.tld and users set their domain's NS to point to: ns1.domainparking.tld ns2.domainparking.tld now the problem is ... few of these domains ...
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HAProxy resolver doesn't work : could not resolve address

I'm on Ubuntu 16.04; I set up HAProxy as an entrypoint to services defined by domain names; those domain names are served by a DNS server (coredns) in the same machine (or VLAN network). Using ...
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1answer
38 views

Sendmail trying to find hostnames in headers for no good reason

I have a client who uses an external mail server to log and filter their inbound email before passing it on to their main mail system (which is Office365). The external server is running Sendmail, ...
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39 views

How to give a server a static IP address with OpenWRT/LuCI?

I have an OpenWRT router and a small home network on 192.168.0.0/24. I have a server which has the static IP 192.168.0.10. How can I set up an A record in OpenWRT/LuCI for it, to give it a DNS name? ...
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2answers
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MX Record Answer Contains Same Domain

What does it mean for an MX record to have an answer section that contains itself? My earlier belief was that this implies that a domain is it's own mail domain, but from running a couple experiments ...
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Server 2016 - AD and DNS setup behind NAT

We have a very bad network installation, with the following hardware and configs: ISP Modem/Router -> Netgear Router -> Netgear FW -> Server 2016 ISP Modem/Router provides connectivity to ...
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42 views

How to configure PowerDNS to return different IP based on client subnet

Our business network runs all over the country. In an effort to provide better, more localized service, I'd like to configure our PowerDNS to return different IP's based on where the client is (by ...
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45 views

Can a DNS server consult another DNS for specific domain name extensions?

For example, suppose I have multiple DNS servers under a private network which handle name resolutions for domains only hosted under said private network. Suppose also I use the name extension .wifi ...
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DNS bind is not working for me

I am trying to configure geo location based DNS. in /etc/named.conf I did following acl "BD" { x.x.x.x/28; }; view "asia" { match-clients { BD; }; recursion yes; zone "example.com" { ...
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Different response from same Windows DNS server for domain and non-domain machines

This relates to a forward lookup zone added to a Windows DNS server. The zone allows machines to connect directly to a local email server when connected to the LAN. The same address resolves to the ...
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CentOS 7 VM running ExpressVPN, cannot mount NFS share while connected

I would like to have internet traffic routed through ExpressVPN, however I cannot seem to mount a local NFS share once connected. I have tried: expressvpn preferences set force_vpn_dns false Because ...
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How can I route public external traffic to consul?

I've setup consul, and can now internaly resolve service hostnames to the appropriate IP. For example: dig @127.0.0.1 -p 8600 tickethub.service.consul ; <<>> DiG 9.12.3-P1 <<>&...
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Repoint website in Azure App Service to Azure static site storage container blob with no downtime

I have a production website in an App Service with 4 custom domains bound to it and two SSLs. I have a newly developed static website that is deployed to a storage container static site $web blob. ...
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40 views

Temporarily Override DNS in Linux for Jenkins Automation

I'm not sure if this necessarily is a jenkins-related question, a Linux-type solution, or just not really possible. I am trying to automate testing for an application in Jenkins. The application runs ...
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1answer
57 views

How to troubleshoot internal DNS resolution (Windows DNS server) pointing to a local server with a static internal IP address

To better explain the set up I have a Debian server in a private network with a static IP. There is a windows AD server that resolves DNS for clients internally. A domain name is already registered ...
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DNS records added based on info provided by Heroku, but URL still not resolving correctly

Awhile ago I registered the domain name www.testapp.id with my registrar (Namecheap). The application I want it to point to is a Rails app hosted on Heroku. I'm following the instructions on Heroku's ...
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42 views

Updated MX Record Causing Bounce

We recently migrated our company to a new mail provider (Gmail), and updated our MX/SPF/DKIM/DMARC records. Checking the DNS propagation via https://dnschecker.org/, all changes are reflected. ...
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How Do I Set The A Record In Office365?

Microsoft is managing my email via Office365 and the nameserver is NS1.BDM.MICROSOFTONLINE.COM. Now I am creating a website using stablehost as the hosting provider. However, if I change the ...
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1answer
33 views

DKIM “default” selector

I often see DKIM configuration guides using default as the selector. Is this a special selector or it is just a convention to use this if you only have one mail server? In other words, if I use the ...
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27 views

Why DKIM validation fails for yahoo, but pass for others?

Why does the DKIM validation for my mailserver fail for Yahoo but nor for others ? I saw this question, but I don't think it's the same issue and the answer was not helpful to me. MxToolbox gives no ...
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1answer
40 views

DNS service discovery and SRV record format conflict

In the RFC 2782 for SRV record type we can read: The format of the SRV RR Here is the format of the SRV RR, whose DNS type code is 33: _Service._Proto.Name TTL Class SRV Priority Weight ...
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Exchange Server 2016 Domain not hosted in the same server conflicts with certificate

I couldn't find any information related to my problem, so I hope you can help me find out a solution for it. We are working with an Exchange Server 2016 in a company that has a domain in a registrar (...
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Keeping DNSSEC KSKs offline with BIND9

I am looking to move the private part of the KSK for my domains off my main nameserver. I've tried this with a test domain and get errors like this: dns_dnssec_keylistfromrdataset: error reading /etc/...
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1answer
137 views

DNS lookup local - how does it work? [closed]

i have installed a server 2019 Active Directory with an DNS server. IP Configuration You can see my DC is the DNS Server (192.168.190.10). 192.168.190.2 is my router. My question: why is it ...
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1answer
28 views

Trying to set up haproxy letsencrypt for ssl termination. gateway not answering dns

trying to set up ssl termination with letsencrypt, but some weirdness is happening with dns. I am routing tcp to the existing host to allow the website at adomain.com to manage its own certs until the ...
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31 views

Reverse DNS Not Working on some Email servers

We host our email on an internal server. Recently we have started getting bouce backs from various other servers. Most seem to have the following error: Reason: Remote SMTP Server Returned: 550 ...
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1answer
75 views

Nameserver responding REFUSED on Centos 7

I have domain registered with godaddy. I had set up custom hostname on godaddy and used same nameservers for the domain. ns1.domain.com and ns2.domain.com (both hostnames are pointing to same ip) Now ...
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1answer
15 views

AWS Load Balancer: changing A record

I have inherited a website that uses AWS for DNS and load balancing. However, the website will be migrated away to another server and won't need load balancing anymore. DNS will remain at AWS. I would ...
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10 views

Web browser DNS doesn't work with OpenVPN on Ubuntu 18.0.4

I am trying to set up OpenVPN to access systems at work. After a few issues with DNS I partially fixed it using the answer here: Openvpn client, force DNS server. On the command line I can now ...
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2answers
42 views

CNAME pointing to domain instead of subdomain

I have a SAAS application which has 3 different subdomains. example.com app.example.com support.example.com I want to White Label the services only in support.example.com Example: testcompany....
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1answer
19 views

External Requests to Internal DNS Server

What would be the best way to configure my internal NAT network to handle external DNS requests? i.e.: Domain 'example.com' is pointed to my public IP address on the WAN port of the router. Internal ...
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1answer
55 views

SOA for DNS delegation

I'll first say that what I'm doing now seems to work, though I'm unclear on whether it's correct. I have a domain registrar company (inherited from a contract) and a name server company, separate ...
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56 views

Unable to resolve DNS over site-2-site VPN between Azure and on-prem

I am running into some issues with setting up a test lab environment between on-prem and Azure. I have got as far as being able to get the site-2-site VPN up and connected and passing traffic (...
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1answer
32 views

Azure DNS does not lookup SPF policies for certain domains

I run my own mail server on an Azure Linux VM with Postfix. Since I was under heavy spam attack I reinforced my mail server security measures. Without going into the security things, today I noticed ...