Questions tagged [reverse-dns]

Reverse DNS lookup is the determination of a domain name that is associated with a given IP address using the Domain Name System (DNS) of the Internet.

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How websites discover subdomains using only 'A' DNS records

Don't 'A' records only return IPv4 addresses? Why do some websites return subdomains? How do they find those subdomains? I mean, are they doing normal subdomain bruteforcing then resolve each ...
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reverse DNS for shared hosting

I have a VPS, I installed cwp on it to creat hosts. this VPS has one IP, I shared this IP in 5 hosts, I maid rDNS for this IP, rDNS address is rdns.aminrezaie.com to IP 192.119.70.158 and it is ...
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How to solve reverse DNS lookup error when mail.example.com is stored on server.example.com

Environment: Digital Ocean, Centos 8, Postfix/Dovecot Background: For my droplet I used a FQDN, server.example.com. Digital Ocean configures the PTR record (reverse DNS entry) on their end based on ...
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DNS Forward Lookup is Failing in Linux

I am installing a two node RAC on my testbed (virtualbox), i have setup the DNS server, forward lookup is not working but reverse lookup is, PFB [root@dbwr1 log]# nslookup dbwr1.localdomain Server: ...
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Squid within docker, rDNS test failed

I build a squid docker container with something like this: https://github.com/sameersbn/docker-squid/blob/master/Dockerfile and I noticed the following problems when starting it interactively: 2020/...
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2answers
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How does reverse DNS add security? [duplicate]

There are plenty of good answers here about how reverse DNS works, but why is it used? It seems that all reverse DNS proves is that the person sending the email has access to the DNS records for the ...
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1answer
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| rDNS | IP gets resolved with a wrong hostname

I've been trying to set up rDNS so my IP could get resolved to my hostname in a program which has a built in rDNS lookup feature. I had done everything I was suggested (ask my ISP to make a PTR record ...
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nginx proxy_pass only when rdns resolves correctly

I have a nginx server on PC_A running as a proxy for a website hosted on PC_B. The server on PC_A provides rate limiting, buffer and cache services for the website. I would like to enable DNS lookup ...
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How to migration a Reverse lookup Zone from BindDNS(master) to existing Reverse Lookup Zone (Primary) of ADDNS

I have 2 DNS Server A (BINDDNS) & B (ADDNS) I have to migrate reverse lookup zone "10.in-addr.arpa" from A to B. The problem is the both Server A & B have configured long time ago and also ...
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DNS, nameserver and domain on the same dedicated IP - PTR record for nameserver?

My dedicated IP: xx.xxx.xxx.59 Am I doing this correctly by having 2 PTR records (ns1 and domain) for my IP? Reverse DNS Zone file 59.xxx.xxx.xx.in-addr.arpa.db $TTL 86400 @ IN SOA ...
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4answers
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in-addr.arpa zone delegation in Bind 9 and Samba 4 as an AD DC with DDNS

Environment and goals In my testing KVM lab I have a virtual network 172.16.50/24, in this network I have got 2 Centos 7 VMs running Bind 9 and ISC DHCP servers: Мастер DNS : controller.wsvirt.home (...
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How to remove DNS Resolution in Haproxy

I have got in a situation where hosts mentioned in the haproxy are resolved into it's ip and sends the request. But in host's server, where they have configured to receive request only with the host ...
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1answer
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Why create a reverse DNS record for every device that connects to a wireless network?

There's this network I connect to often. After some experimentation, I figured out that when you connect to the network, the DHCP server assigns you an FQDN that usually follows the scheme <your-...
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1answer
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Understanding TTL field of PTR record returned by dig client

I have some doubts about working of DNS in general - even given the fact I have theoretical base. let's consider a following output: [user@host ~]$ dig google.com [...] ;; ANSWER SECTION: google....
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Configure reverse lookup zone on AWS Simple AD DNS Servers

I would like to configure a reverse lookup zone (0.20.in-addr.arpa) for a bunch of EC2 hosts in a VPC that is pointed to the AWS Simple AD DNS service. I initially thought that this could be done by ...
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1answer
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Who is responsible to set up reverse DNS (PTR) for a domain, the DNS host or the MX host?

I have the dns for a domain on GoDaddy and the MX configured for Gmail. All set up ok with spf, dkim and dmarc, and all passes all online tests, beside: intodns.com reports this error for the domain ...
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rDNS for EC2 server not applying

I have an EC2 server that hosts our website where we send some mail from (contact forms). I have noticed that the rDNS is not properly working. When I login to the server and type hostname it returns ...
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1answer
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Can't send email to some servers

I get this error below, after I send email to some domains including charter.net SMTP error from remote mail server after MAIL FROM:<******@mydomain.com>: 550 5.7.1 Connections not accepted ...
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1answer
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What is Wrong with My Reverse Lookup PTR Record

I can't figure out why my PTR record does not work on my new server. This configuration worked on my old server and I already confirmed with my host that they added a record on their end so that 72....
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2answers
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Client PCs cannot connect with DCs on specific ranges

Sometime last week (while I was on leave) something changed in my network/domain which I cannot pinpoint and we have the below behavior. My 2 DCs are 2008 R2 and are on a 10.2.128.0/24 subnet (as ...
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1answer
555 views

PowerDNS Not Answering Reverse Lookup Queries

I have PowerDNS Authoritative & Recursor running on a server in my environment. When I use this node as my a DNS Server, it responds to A record queries without any issues. However, when I attempt ...
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1answer
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SPF and IPv6 fails even if the reverse DNS is created

When sending mails to Gmail I get this error Received-SPF: fail (google.com: domain of test@domain.com does not designate 2a01:4f8:xxx::2 as permitted sender) client-ip=2a01:4f8:xxx::2; When I ...
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1answer
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BIND cannot see local client PCs and vice versa

I'm trying to configure bind9 DNS to make it usable for my tiny network of windows PCs in order to create Active Directory DC on samba. For some reason I am getting "ignoring out-of-zone data" for ...
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2answers
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Deny foreign domains requests with bind9

I have 2 bind9 servers adjusted as Authoritative-Only DNS Servers. I've noticed that dnstop shows a lot of requests for foreign financialresearch.gov domain (not mine). There are more than 50k ...
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1answer
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Caching BIND server not returning RFC1918 PTR records

We have a Debian stretch server running Bind 9.10 as a local caching DNS service to applications running on that server. This local caching DNS service sends its queries to our institution's main DNS ...
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2answers
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Should full hostname of email server be set in the DNS Zone Settings?

We are using a rented VPS as an email server. Lets say the email domain is example.com. The nameserver for example.com is a different server. rDNS for the VPS can be set on the hosting side. In order ...
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2answers
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Using multiple PTR (rDNS) on a GC Instance

Setting up multiple reverse DNS entries is super simple in linux but I cannot find documentation on doing it in google cloud. I see how to add one, but not how to add several. The server hosts ...
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VPC DNS propagation issue

We're working on AWS VPC. We have a VPC containing several ECS tasks. For a given task, we'll get its public IP, then reverse DNS it to get its public hostname. Once we get the hostname, we'll ...
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2answers
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DNS Manager, how to add an internal IP address to point to Office365 SMTP URL

Here's the short version: I'd like to add some sort of record in DNS Manager such that all SMTP messages sent to an arbitrary internal static IP address get sent instead to the URL smtp.office365.com ....
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1answer
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How to set up a reverse mapping zone for a personal domain?

I've been trying to figure out how to set up a reverse zone based on an already existing forward zone, but I keep getting an error saying server can't find xx.xxx.xx.xxx.in-addr.arpa: SERVFAIL ...
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1answer
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How can this tool find out registered domains from an IP address?

This is one that I've never really known how to do, and it's been nagging me from time to time for years. I've read all I could find, including all the answers here. None of them gives a real answer ...
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1answer
119 views

Is an rDNS PTR record really necessary to avoid spam filters?

I realize this is a somewhat abstract question, but does anyone have any experience with setting up an e-mail server without an rDNS record? I ask because I really want to host my mail server at home,...
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1answer
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dnscache does not return PTR records

I am working on setting up tinydns to serve DNS data for my local network (several virtual machines, actually) and dnscache to serve both data about my local network and big internet. So, here is my ...
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mail not working pointing at old server

Hoping you can help, I'll preface to say that I'm working for a small company and I'm the "IT Guy" as I'm not sure what to ask google, and I've searched here for hours, and still no closer to an ...
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1answer
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rDNS issue in Cloudflare and AWS ec2 instance

I have installed centos7, whm/cpanel and mailwizz on amazon ec2 instance, managing DNS through cloudflare.com. Everything is fine i have issue with rDNS even i have created PTR records in Route53 and ...
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1answer
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[DNS][BIND9] Forward to external IP when clients request external domain name

So, I have some dns where I have setting with many internal zones for my domain yyy.com. And I need add record to provider server (host - with configuration files to download, this not some DNS like ...
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2answers
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domain name system - rDNS is not exist [closed]

I need some help with Reverse DNS as I have got a problem with it. I have setup rDNS on my hosting provider which I use rdns1.example.com and I have a server hostname which it is gateway1.example.com. ...
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PowerDNS AXFR - ;; communications error to x.x.x.x#53: end of file

Using PowerDNS, we got into an issue with transferring a single domain object (/24) from our primary to our secondary DNS server. This /24 is part of a larger RIPE block, /22, and is not ...
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MTA poor reputation [duplicate]

I'm facing MTA poor reputation and I'm fighting against it since days without success. MTA poor reputation had plenty topics so I verify/modify many aspect of my configuration such as: Verify ...
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1answer
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rDNS — more than one IP per server?

Very simple question that I can't find a reliable answer to, with Google -- can my server be the reverse DNS for multiple IP addresses? Is it bad practise / wrong / asking for trouble to say my ...
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1answer
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Nginx bind to external IP only (listen hostname:port)

I'd like to specify an nginx server that listens only on external IP of an hostname given in listen directive. My server has domain name foobar.example.com which resolves to public IP 1.2.3.4. When I ...
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1answer
112 views

Having multiple A records to get forward rDNS to work

Running a Droplet on DigitalOcean with Apache and a mailserver on Ubuntu. I've managed to get SPF, DKIM and DMARC working on this server, but Reverse DNS is something that I've never figured out. I ...
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1answer
627 views

PTR not showing in dig request

I am trying to set up a PTR for reverse DNS so that mail that gets sent from me scripts doesn't get blocked due to reverse DNS failure. I beleive my zone is set up correctly, however me "thinking" it'...
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1answer
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Custom resolv.conf file

Is there any way I can specify a custom resolv.conf file (instead of /etc/resolv.conf) in RedHat Linux, similar to specifying custom hosts file via export HOSTALIASES=~/my_hosts? I don't have root ...
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1answer
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ISC-DHCP-SERVER adding incorrect reverse zone entry

I have ISC-DCHP-Server and BIND9 running on Debian Stretch. I am trying to setup Dynamic DNS for my client computers, but I'm struggling with the reverse zone. Currently, when computers request an ...
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2answers
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How to set up external DNS?

I have few appliances that are HTTP/HTTPS managed and assigned PUBLIC IP ADDRESSES and I need to set up DNS name resolution so I can access externally by it's name. How to set up external DNS?
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1answer
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DNS is slow to resolve after force removal of a domain controller

On a Windows domain I recently had to do a "force removal" of a domain controller. I was careful to remove all the metadata and did a metadata cleanup. I also removed all references to the domain ...
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1answer
29 views

distinct mail and web hosting servers with multiple domains; spam-avoidance, PTR and SPF records

Context. I have multiple domains web services being hosted on a Digital Ocean droplet (Ubuntu and Nginx in stack). Apparently, DO automatically sets up a PTR record. However, when I query host <...
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2answers
3k views

Windows AD DNS is automatically adding PTR records for CNAMEs and I want this to stop

Preface: I am not a Windows admin. I am a Linux admin. I have a Windows 2016 server with AD DNS that handles internal DNS forward and reverse lookups. Somewhere, somehow, some process is ...
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1answer
656 views

Spamassassin - how to get a better score

I am testing a contact form, but I am getting a too high score for the emails sent from the contact/booking form. Here is the header: Return-Path: <yyy@host49-253-177-94.static.arubacloud.com> ...

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