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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Linux PCs sending “ICMP udp port unreachable” to DNS server

So digging around in my syslog I have been noticing a lot of ICMP packets being flagged by our ASAs: %ASA-4-313005: No matching connection for ICMP error message: icmp src Internet:x.x.21.122 dst ...
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Is it valid to have several IP addresses resolving back (PTR) to one name that doesn't match either of the relevant A records?

I have several devices, each with its own IP address. There are various names pointing to these addresses (in several different domains). As an example the device with IP address 10.0.0.1 is known ...
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1answer
42 views

reverse dns configuration not working

I am configuring my reverse dns server, after installation then I run the following: nslookup 110.74.133.89 Server: 192.168.101.4 Address: 192.168.101.4#53 ** server can't find ...
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2answers
37 views

multiple ptr record in bind

I'm running some small ISP here and I own couple of IP ranges. I have given a few public IP addresses to some of my customer and they are running mail servers on them. They have demanded me to add ...
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2answers
75 views

Reverse DNS is not a valid hostname [closed]

I help a friend run a server, which includes a mail server. http://mxtoolbox.com reports that our reverse DNS is not a valid hostname. The reverse DNS currently points to domain.com. Should it point ...
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1answer
106 views

Reverse DNS is not a valid Hostname error from MXToolBox

I can't send email messages from my server. However, I can receive email messages. I set up my server the exact same way I did many times which I've proven it works and it's pretty straightforward and ...
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11 views

dnsmasq classless reverse forwarding

I'm currently using a dnsmasq as DNS forwarder for a handful of classless zones and the A record forward is working fine. But I now do have some trouble with the PTR query forwarding, since I don't ...
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1answer
24 views

Public domains and hosts resolving to 127.0.0.1

Our security systems are going crazy alerting us that hundreds of external DNS queries and responses are resolving to addresses like 127.0.0.1 and sometimes 0.0.0.0 to requests originating from our ...
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1answer
33 views

Reverse DNS query of public IP returns localhost

I'm seeing this unusual behavior with reverse DNS lookups on this public IP Address: 222.253.228.79. Can someone explain what's going on? MXToolbox PTR lookup resolved localhost as the domain ...
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17 views

exim4 mail relay for multiple domains

I have hMailServer running on a Windows 2012 box and exim4 running on a separate box. However, I would like to continue configuring my email accounts on the Windows server (via hMailServer), but relay ...
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0answers
41 views

Why does my box keep sending reverse DNS queries and how to stop it?

Situation My box keeps sending reverse DNS queries about our LAN hosts. Obviously they all fail because they are private addresses. Request Source: 192.168.1.6 Destination: 192.168.1.1 (default ...
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1answer
34 views

How to map subdomain to a domain with CNAME?

I would like to point CNAME records for www.example.com to sub.example2.com. The hosting for example2.com is a shared hosting (cPanel without Addon domain feature). So, what I did was to add a ...
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1answer
26 views

nslookup how to get list of domains in a DNS server

I want to list all domains In a DNS Server. More details: spouse that foo.com is a web hosting company and ns1.foo.com is their DNS server. the web sites foo1.com to foo100.com are hosted by this ...
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2answers
51 views

Removing DNS entries

I've got the following DNS records and I would like to ask if it is OK/safe to remove the unwanted entries: admin/ftp/m/mail/webmail (I hope the mail one doesn't affect the emails?) @ IN NS ...
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1answer
37 views

Syslog-ng reverse dns lookup for data fields

I would like to try a reverse-dns before storing the firewall logs. I know this is possibile in logstash but i don't know if syslog-ng can be configured to do the same. Actually my logs coming from ...
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2answers
196 views

What should my reverse DNS be for my inhouse email server?

So I have an inhouse exchange server for the domain visaustralia.com. (email addresses are email@visaustralia.com) And when checking the reverse DNS of my static IP address with ...
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27 views

Mailserver complains about reverse DNS lookup on my Gateway

I am presented a mail server setup, that is working well. There's only a small issue, which makes me think, there's something wrong in the DNS setup. It is a small setup with a Debian mail server ...
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65 views

Windows DHCP server not discarding PTR records when an address is leased

Got the following setup regarding DHCP & DNS: Windows Server 2003 doing DHCP Windows DNS (different server)authoritative for the forward zone BIND DNS (on a UNIX server) authoritative for the ...
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213 views

rDNS 'zone [xxx] has no address record (A or AAAA)

teaching myself some server tricks. Getting trouble with bind9 on debian8. named-checkzone pro.lan db.pro.lan.inv zone pro.lan/IN: NS 'server.pro.lan' has no address records (A or AAAA) my ...
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63 views

rDNS and forward DNS for mail server behind firewall, different IPs

All, Here is my setup : Firewall(x.x.x.114) <--> mail.mailserver.com (FQDN) (x.x.x.118) When sending mail, header has following IP ...."Receivedfrom mail.mailserver.com ([x.x.x.114])", my ...
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1answer
57 views

Not able to load reverse zone with bind

I've created a simple bind dns server to host 3 zones in a test lab. bath.local (192.168.100.0/24) munich.local (192.168.101.0/24) dhcp.local (192.168.99.0/24) I want forward and reverse ...
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1answer
881 views

Reverse DNS does not contain the hostname error from MXToolBox

I am not sure where I have gone wrong in my configuration but I am getting the error Reverse DNS does not contain the hostname for my domain sparkdojo.com I had the hosting company set the PTR record ...
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2answers
184 views

SMTP Reverse DNS Mismatch Reverse DNS does not match SMTP Banner

I wonder if you could help me? I have set rDNS to mail.simplyislam.biz for IP 178.32.48.104 with my hosting server and also in DNS control panel. However, I am still failing this test: ...
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174 views

Is having the same PTR hostname valid for multiple ip addresses? [duplicate]

Currently I have the following setup with two hostnames and two ips: cheeze1.mydomain.com IN A 123.123.123.111 111.123.123.123.in-addr.arpa IN PTR cheeze1.mydomain.com cheeze2.mydomain.com ...
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Client unable to resolve nslookup after settingup dnsmasq in server

I have installed and configured dnsmasq in server box. I am able to perform nslookup in server but unable to resolve server hostname to ip in client. Giving error "server can't find puppetmaster: ...
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1answer
63 views

Specify destination DNS server based on subnet

Our office subnet is 10.1.10.0/24. I have a gateway (10.1.10.1) that is forwarding DNS requests to a server running DNSmasq (10.1.10.2). I have an IPsec tunnel to our Parent Company's network ...
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235 views

Reverse DNS error

Today I changed my DNS and nameservers to Cloudflare. After that, pingdom gave some strange DNS errors. I searched the internet but couldn't find a solution. The errors are: Could not find reverse ...
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1answer
139 views

Spamassassin RDNS_NONE matches, but there is a RDNS

I got a a little problem - spam assassin's RDNS_NONE-rule matches on my outgoing mails but there is a RDNS set for all hosts, that are in the delivery-chain. If I send an Email to ...
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1answer
86 views

AWS DNS Error - SERVFAIL

So I have followed the configuration guide provided by Amazon (http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/CreatingNewDNS.html), but I cannot get the URL/Domain to be send out to the name ...
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1answer
120 views

Configuring Reverse DNS on Windows Server 2008, can't send email

I run a VPS on a Windows Server 2008 machine, and since I got it in January 2015 everything has been running fine, the server has IIS, DNS, and uses Mailenable for email exchange. I've been running ...
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226 views

Reverse zone not working with BIND9

I'm trying to configure a DNS server in UBUNTU 12.04 with BIND9 service.I'm able to successfully configure the same and the when I'm executing nslookup command it works well.However,the host command ...
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How can I make Windows DNS Scavenging to begin immediately?

I turned on scavenging for a single reverse zone, defaults 7 days for both. I then right clicked on the server and selected Scavenge stale resource records. I looked a the reverse zone, clicked ...
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206 views

Postfix on server with multiple IP addresses sends mails with wrong HELO in header

I have a VPS with multiple IP addresses: venet0:0 x.x.x.2 venet0:1 x.x.x.3 venet0:2 x.x.x.4 venet0:3 x.x.x.5 All IPs have A records m2.domain.com -> x.x.x.2 m3.domain.com -> x.x.x.3 ...
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1answer
116 views

Hotmail/Outlook dumping apparently valid emails

I've written some software that operates a non-commerical contact list for clubs, where the server sends out admin mails to the entire club. The emails are received Ok on Yahoo, gmail, and AOL, but ...
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0answers
106 views

Centos-bind: Reverse DNS failed

Hi Server fault member, I need to setup a reverse DNS for my client. There have 3 IP ranges on the rDNS server. The server system is Centos 6.5 with bind 9 Let me describe my situation. I have a ...
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1answer
132 views

Can I setup the PTR records of reverse DNS with different IPs?

I am very new into the Linux world. I'm trying to configure 3 Authoritative-Only DNS servers. I got everything set up, except for the zone of in-addr.arpa. I have the following servers with the ...
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1answer
147 views

Is it possible to set up a reverse DNS record on AWS for address from a different registrar?

I don't have control over the registrar for the domain we use but the elastic ip and domain have been registered to each other - now I need to set up a mail server on my EC2 instance and therefore be ...
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58 views

What can happen with wrong rDNS?

I noticed, that i had the rDNS for some server wrong. It did not cause any problems, but i am wondering, what can happen with wrong rDNS except from obviously getting spam point or even mail rejected, ...
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1answer
78 views

How Reverse DNS works?

I was reading pretty a lot, but still can't get it. For example we have example.com, 127.0.0.1 and 1.0.0.127.in-addr.arpa for example Forward DNS is simple. example.com points to 127.0.0.1 What is ...
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votes
1answer
285 views

my host has no PTR record [closed]

when i check my host i get this host myIP xx.xxx.xx.103.in-addr.arpa has no PTR record So i dd this to my /var/named/domainname.com.db myHostname. IN A myIP xx.xxx.xx.103.in-addr.arpa. IN PTR ...
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1answer
37 views

What should be the reverse DNS for the email server?

When I nslookup x.x.x.x my web server's IP address I get this error: Non-existent domain. Must it return the top domain like mydomain.com or it is okay to return ...
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2answers
272 views

mx server: multiple domains on one ip

I'm just a bit confused about the correct DNS setup for hosting multiple domains on a single server with one ip. For example the mail server (domain/reverse: example.com) should host 3 domains: ...
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2answers
1k views

CentOS Cannot resolve any hostnames

I am trying to set up a server(PHP/HTTPD) in CentOS. When I use ipaddress to access the website its working fine. But using domain name its not working. So I used ping command to check. ping ...
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1answer
142 views

nslookup does not work on certain IP address [closed]

when I gave nslookup 74.125.236.200 Server: 192.168.5.11 Address: 192.168.5.11#53 Non-authoritative answer: 200.236.125.74.in-addr.arpa name = maa03s17-in-f8.1e100.net. ...
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110 views

How do I restrict the domain name for reverse DNS updates with bind and nsupdate?

I've set up Bind to allow hosts to update only their own DNS entries, but I'm having trouble with the reverse DNS portion of this. My configuration is as follows: named.conf options { listen-on ...
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91 views

Captive portal and walled internet

I am creating a tour guide app which visitors can download when they arrive on location. There will be a Hotspot to which they connect, they will get a welcome page with instruction (and a button to ...
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2answers
451 views

Do I need to Set-up PTR record in SPF Setting?

I have set-up the RDNS from my hosting provider for the ip address to resolve to "maximus.example.com". After that, do I also need to add the PTR records to the SPF Text details in my DNS zone file as ...
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1answer
110 views

Returning mails - revDNS + Helo command rejected: Host not found [closed]

i've got a VPS server and directadmin with multiple domains on it. I've noticed annoying problem with email sending on one of domains. Sometimes when I send email to client it bounce to me with ...
2
votes
1answer
106 views

Is it possible to set a PTR record for Github Pages hosting?

Icelandic domains (.is) require that their domains support reverse DNS, which means configuring PTR records on the hosting server. Is it possible to set up a PTR record for GitHub Pages site hosting? ...
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89 views

IPv6 record will not take for rDNS

I added the following to named.conf zone "3IP6.A.B.C.ip6.arpa" { type master; file "3IP6.A.B.C.ip6.arpa"; allow-update { none; }; }; I then created my dns zone record called 3IP6.A.B.C.ip6.arpa ...