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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Cisco DNS doctoring or Hairpinning?

I've the following configuration: CISCO 881, IOS 15.2(4)M6. On WAN interface is configured the 86.34.156.48/29 subnet from our ISP. Behind the router is staying 2 webserver. NAT: 86.34.156.51 <> ...
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8 votes
1 answer
2k views

DNS and Active Directory configuration for a branch office

We've got a branch office with no on-site services at the moment, and we'd like to change that. The biggest goal is to setup some file servers but faster logins and DNS resolution will be welcome as ...
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6 votes
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Caching, forwarding Bind 9.9.4 server works for weeks, suddenly SERVFAIL on all queries (rebooting fixes it)

I have bind 9.9.5 running on two servers (CentOS 6 and 7), for caching and forwarding DNS queries for a mail server. The servers run fine for weeks, then suddenly respond to all queries with SERVFAIL. ...
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5 votes
0 answers
3k views

BIND: DNS failover and high availability with dynamic updates

I am trying to design a system with 2 servers that act as both DHCP and DNS servers with dynamic updates. I am using ISC DHCP and BIND9. It looks like this. Server1 - DHCP primary and DNS master. IP ...
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5 votes
1 answer
34k views

CentOS 7 Unable to Resolve Any Host Names

New to Linux and looking for friendly assistance. My company is re-configuring our network DNS infrastructure to point our internal DNS servers at two new CentOS 7 / BIND 9 machines in our DMZ ...
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5 votes
0 answers
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Understanding (and partially disabling?) DNSSEC for an internal domain

I am setting up a new DNS infrastructure for our internal HPC cluster environment. This involves providing a migration path from our existing DNS authorities and domains. For sake of example, let's ...
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5 votes
0 answers
4k views

can't access sub-subdomain: DNS_PROBE_FINISHED_NXDOMAIN

I can't access to sub-subdomains. For example http://electricien.synerciel.fr is working. But, for sub-subdomains http://electricite-lemonnier.electricien.synerciel.fr/ returns ...
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  • 488
5 votes
1 answer
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Mac OSX Server 10.6 DNS Issues

The server was upgraded from 10.5 from 10.6, during the upgrade the Reverse Zones were lost so I tried to recreate these but found that it's best to delete all zones, definitions and start again. So ...
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5 votes
1 answer
14k views

curl and wget attempting an ipv6 connection

On my dedicated server (hosted by OVH), that is running a fresh install of Ubuntu 14.04, curl and wget take approximately 10 seconds to complete a simple request. $ curl -v google.com * Rebuilt URL ...
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  • 405
4 votes
0 answers
606 views

ssh - How does the option CheckHostIP=yes really help me?

There are many discussions about this option and most people argue that "it improves security", "it protects you from MiTM attacks/DNS spoofing", etc, but I fail to see how that is ...
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  • 196
4 votes
1 answer
534 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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  • 559
4 votes
0 answers
210 views

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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  • 143
4 votes
0 answers
371 views

How to enable hostname resolution (dns) for lxd containers from the lxd host?

How to enable lxd hostname resolution from the lxd host? After creating the below container: >>> lxc launch ubuntu: container Creating container Starting container >>> lxc list +--...
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4 votes
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DNS IPv6 settings on Domain Controllers

Both in my lab testing and on real installation I saw that, after a dcpromo (done via "Server Manager" on Windows 2016), a loopback IPv6 address is automatically added on the interface DNS settings (...
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4 votes
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Getting to enforcing google safe search using CNAME with unbound and nsd?

I am trying to implement this using Unbound and Nsd: https://support.google.com/websearch/answer/186669?hl=en To force SafeSearch for your network, you’ll need to update your DNS. configuration. ...
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  • 41
4 votes
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482 views

DHCP Server Listing Host as "BAD_ADDRESS" and not Registering DNS

Question Why is DHCP showing "BAD_ADDR", why does it think there is a Conflict, and why can't the host register its DNS name? Devices: DHCP Server = Server 2012 on bare metal. Also running DNS. ...
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4 votes
0 answers
796 views

Unable to Join domain, unable to resolve hostname

I'm having problems connecting a computer to the domain. I'll explain my setup (with hostnames). I have: Hyper-V Guest 1 (Imperium) - DC / DNS Server (Server 2016 Essentials) Hyper-V Guest 2 (Lima) ...
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4 votes
0 answers
277 views

Bind notifies on DNS views

I have configured two Cent OS based DNS servers one for master and one for slave with internal and external views for a domain. The problem is that i get notifies and automatic zone updates when i ...
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4 votes
0 answers
2k views

Registrar nameservers vs. NS records for bare domain?

OK, I'm a bit new to DNS, but I'm having some trouble finding the answer to this. I have a domain registered at google domains. As with other registrars, you have access to their free DNS, and ...
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4 votes
0 answers
783 views

How do I set up openshift’s bind correctly

I have set up an instance of redhat’s Openshift origin and am sometimes having troubles resolving the individual apps’ domains from the outside. I have two physical machines running, both with their ...
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4 votes
0 answers
570 views

Does AWS Elastic Beanstalk Swap Environment Url swaps environments for git push?

I have read the docs for zero downtime on aws but cant seem to understand what happens in this scenario? I have a environment running in production called 'red' I duplicate the environment as 'blue' ...
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  • 151
4 votes
0 answers
4k views

Force Windows to use only TCP for DNS lookup

I have a broken (badly configured) VPN network that I cannot change. The remote gateway will route all UDP traffic for port 53 to a special DNS service. But I need to use a different DNS server also ...
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  • 372
4 votes
0 answers
4k views

vmware DNS in host-only configuration

I want to connect a Linux VM running in VMWare on a Windows 7 laptop to an enterprise network using host-only configuration. I was able to setup bidirectional routing between "host-only" VMWare ...
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  • 354
4 votes
2 answers
810 views

Windows Server 2008 R2 DNS - Syncronizing changes to TTL

I apologize if this has been asked. My searches have not been successful. If I have 2 DNS servers in my Domain and add an A record to 1 server, that record is successfully propagated to the second ...
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  • 143
4 votes
1 answer
743 views

Zone transfer Windows Server DNS from NSD

I have a NSD server being primary server for a zone and want a Windows Server (2008 and 2012 RC) box to be secondary for that zone. Everything is configured and working EXCEPT: When Windows receives ...
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  • 41
4 votes
0 answers
924 views

Ubuntu SOCKS proxy setup with two interfaces - how to pass DNS

I setup a SOCKSv5 server (Dante) on Ubuntu with two ethernet interfaces: eth0 is connected to my WAN with a static routable IP eth1 is connected to my LAN with a private IP I have a client ...
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  • 163
4 votes
2 answers
809 views

DNS delegation on same server with DDNS and second slave server

I have two servers running BIND, the first is setup as the master of two zones and the second as a slave for those zones. The zones are example.com and ddns.example.com. I have DDNS running and ...
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3 votes
0 answers
267 views

Q: Configuring dnsmasq to filter A or AAAA queries

Can I configure dnsmasq to respond to either ipv4(A) or ipv6(AAAA) queries only? I am using dnsmasq to forward queries from an internal subnet to a WAN connection. Unfortunately, sometimes I will only ...
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3 votes
0 answers
174 views

How to add/change NAPTR records to a specific ZoneScope in Windows DNS using PowersShell

I'm using DNS Policies in Windows DNS for split-horizon. I need to add NAPTR records which resolve differently based on the subnet of where the request came from. I've got almost all of it figured out,...
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3 votes
0 answers
302 views

Supporting IPv6-only clients in connecting to IPv4-only hosts

I have a service that aggregates third-party content, but ultimately end-users connect directly to the third parties they're interested in. The problem I'm facing is that many users are connecting ...
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  • 131
3 votes
0 answers
973 views

DNSSEC for private internal sub zones of an external domain

Consider the following scenario: example.com is hosted on CloudFlare and it's signed by CloudFlare DNSSEC. Everything works as expected for example.com. Inside the company we have some internal ...
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3 votes
0 answers
6k views

Server can't find domain: SERVFAIL

I have VPS and CentOS7 installed on it. Also I have httpd Apache2, nginx, named and iptables services working there. First, when I just bought this server, I had hostname maindomain1.com and made my ...
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3 votes
1 answer
5k views

Adding a new DNS server with systemd-resolved

To access other machines on my network by their name, I have to add the following two lines to my /etc/resolv.conf: search foo.local nameserver 192.168.X.Y But any changes I make do not persist ...
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  • 131
3 votes
0 answers
34 views

How should private network services be exposed to users using DNS over HTTPS?

As DNS over HTTPS becomes more widely deployed, I am starting to hear reports that users are failing to access services from internal networks when DNS over HTTPS is turned on. Fair enough, DNS over ...
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  • 210
3 votes
0 answers
245 views

Why does Apache need such a long time for initial connection?

I am running apache 2.4.18 on ubuntu. Serving about 500.000 PI per month. No big deal without peaks. Somehow it started now to take a long time for the initial connection, after restarting apache it ...
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  • 1,993
3 votes
0 answers
379 views

Different nslookup answers on different clients in local network with local DNS

Situation: I have a few clients in a local network. I have a server named amp003 with IP address 192.168.4.13 I have two DNS servers (each one on relative DC server). On client 1 I did following: ...
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  • 41
3 votes
0 answers
3k views

Dnsmasq unable to resolve local host

I'm unable to get my local DNS server to work and totally stumped. Here's what I have done so far to make it work... Dnsmasq configured on Ubuntu 18.04 ( Static IP: 192.168.1.100) /etc/resolv.conf ...
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  • 41
3 votes
1 answer
383 views

Is it possible to change sendmail behavior on "Host unknown" errors?

Sendmail 8.14.4 I had DNS issues resulting in a DNS server thinking that a hostname wasn't available (when in fact, it was available). That resulted in the following delivery log entry in sendmail: ...
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3 votes
0 answers
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Unbound refuses requests from localhost even though `access-control: 127.0.0.1 allow_snoop`

This is my unbound.conf server: interface: 0.0.0.0 access-control: 10.0.0.0/8 allow_snoop access-control: 127.0.0.1 allow_snoop access-control: 192.168.0.0/16 allow_snoop ... Reading the ...
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  • 190
3 votes
0 answers
3k views

Mailgun emails are rejected everywhere but on Gmail

My problem and Mailgun logs I've "setup and verified" (see context) my sending domain with Mailgun, so I could use it to deliver my contact/order forms via Mailgun API: https://github.com/...
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3 votes
1 answer
5k views

request has invalid signature: TSIG rndc-test-key: tsig verify failure (BADKEY)

I am pretty much new to bind DNS and during nsupdate , i am getting BADKEY error.I have /root/named/chroot/etc/rndc.key as below :- key "rndc-test-...
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3 votes
2 answers
2k views

Windows server ignoring DNS resolution on private interface

I have a Windows 2012 server with two interfaces - public internet facing, and private. The private interface uses our internal DNS servers. This interface has no gateway. Static IP - not DHCP. I ...
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  • 228
3 votes
1 answer
795 views

Search option in resolv.conf getting overwritten by prepend statement in dhclient.conf

I have setup a DNS server for my department which is running FreeBSD 10.2. It is currently connected to the campus internet and receiving its address via dhcp, so /etc/resolv.conf looks like this: #...
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  • 31
3 votes
1 answer
1k views

Error using dnssec-signzone in chroot'd bind 9.8 when a zone file includes other files

Using bind 9.8.2 on RHEL 6.5, running chroot'd. I have a zone file that includes other files (it's a zone with a large number of servers in different datacenters, and there's one included file per ...
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3 votes
0 answers
724 views

How to disable IPv4 use on OSX (Or disable Happy Eyeballs)

I have a OSX El Capitain (10.11.2) host that has only IPv6 connectivity. The network uses NAT64 and DNS64 to provide access to legacy IPv4 hosts on the internet. The problem is that when looking up a ...
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3 votes
1 answer
2k views

How to use nsupdate to update a wildcard dns record

So for our dev environment we have a wildcard A record for each of our developers. Having different needs (vpn vs office, etc) we allow update on the dns via nsupdate. That works pretty well but I ...
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  • 131
3 votes
2 answers
918 views

Why is sendmail calling dns_getcanonname for domains of non-recipients in the To: header?

We've noticed an occasional repeatable problem in our sendmail config. The scenario is we receive a message from the internet with one of our users in the To: list, and one of the other users in the ...
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3 votes
0 answers
5k views

DNS Failure From Cisco AnyConnect SSL VPN Subnet

We have three Windows Domain Controllers (2012 R2 and 2008 R2 mix), all DNS servers. Split-zone DNS scenario. DNS resolution is working for all internal subnets except over User VPN. All network ...
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3 votes
0 answers
2k views

No RRSIGs found

I had a dnssec expiration and since redoing everything, I get the following error No RRSIGs found from verisign debugging These are the exact steps I use to produce the key and signatures. What ...
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  • 197
3 votes
4 answers
3k views

Multiple domains (with & without www prefix) on same server, running the same code

We've inherited the following website setup: one main website and around 130 secondary websites, which all point to the main website domain (through a CNAME DNS setup); Website is hosted on an IIS 6 ...
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