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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.

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

Computer networks use the Domain Name System to determine the IP address associated with a domain name. This process is also known as forward DNS resolution. Reverse DNS lookup is the inverse process, the resolution of an IP address to its designated domain name.

Source: Wikipedia.

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Network outage - Mapping, Checking network, BGP, Traceroute, RIPE

At first, I'm not able to name my question properly, so this will be adjusted I recently experienced an international network gap. Mean when some part of world wide network is unavailable. I'm able to find out using ping,traceroute,nmap tools where…
Marek Sebera
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Bind Zones split by octet

Why are the reverse Zone files in Bind split by octets instead of subnets? This is what I would expect to see: subnets: 172.0.208/22 10.0.2.0/25 10.0.2.128/25 host# ls…
frogstarr78
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How would I setup reverse DNS for 2 email servers?

I have an interesting DNS question (well interesting to me atleast). I just installed an hmail server in our remote office to act as an MX backup in the event our exchange server goes down. The 2 host names…
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Disable reverse PTR check in Zimbra and force accept from invalid domains

I've moved an older Sendmail/Dovecot system to a Zimbra community edition system. I need to be able to receive messages from certain standalone Linux hosts that may not have valid A records or proper reverse DNS entries established (e.g. AT&T is the…
ewwhite
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Reverse DNS not resolving for IPv6 addresses in BIND

Reverse DNS entries for IPv6 addresses are not working. Everything I've read on the subject says the following configuration should work: In named.conf: zone "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.3.0.0.0.0.0.c.7.5.0.6.2.ip6.arpa" IN { type master; …
Ernie
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DNS resolving error

I am using a linode running nginx. I wanted to have mail sending capabilities on my VPS, so I change the hostnames and reverse DNS but now I have messed up my DNS somehow and the site doesn't even resolve. Here is what my DNS manager for the domain…
Ashfame
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ISPs and reverse DNS lookups

I read in easyDNS that, in order to set up reverse DNS, "The IP block must be delegated to our nameservers by your ISP." Is that always the case? What if you decide to host your name servers? Will adjusting the PTR records suffice? Some discussions…
ezequiel-garzon
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Exchange 2007 Delivery Delayed (maybe need certificate?)

Last week, I setup a new domain and Exchange Server 2007 SP1. I created new accounts and mailboxes for my 30 users and imported all mail from their old domain to this new server. It's a Hub Transport on a Windows 2003 Server R2 SP2. I don't have an…
HighTechGeek
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Reverse DNS lookup takes 5 seconds to give up

I have a Debian 2.6.26-2-xen-amd64 system which takes 5 seconds between the second and third failed reverse DNS lookup. All (most?) other similar systems here do the three lookups with little wait between them. I have tried to figure out what might…
Daniel C. Sobral
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Does sending e-mail in the name of customers increase the risk of being marked as spammer?

We are developing a SaaS website application that lets users send invoices to their clients. Ideally, these e-mails should appear to be originating from our customers, so the sender e-mail address domain will not match the reverse IP entry for our…
Adrian Grigore
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When does unbound fully drop expired cache

How long it will hold expired cache before dropping it? Is there any way to prefetch expired cached instead of dropping it?
zer09
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Wireshark find DNS response "Refused"

I'm looking for a way to filter a packet capture in wireshark for instances where our server responds with "Refused" to a recursive DNS query. dns.resp.type== doesn't seem to offer anything that I see as a match to my request, do I need to look…
tink
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Reverse DNS record is not recognized

I have a problem creating a reverse DNS record. First of all, I have created a new zone. IP was aaa.bbb.ccc.ddd and Domain was ccc.bbb.aaa.in-addr.arpa. Second, I have edited the just created zone and I added a PTR record:ddd IN PTR domain.com, TTL…
jstuardo
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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 the droplet name. This works fine with my web…
myNewAccount
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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 test the IPv6 2a01:4f8:xxx::2 reverse DNS…
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