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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78 views

Wildcard DNS like “*-test.example.com”

Is it possible to set up a wildcard domain like "*-test.example.com"? The main reason I'm asking is because I'm in the process of setting up Continuous Integration with Jenkins, and we'd like to ...
5
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2answers
151 views

How to determine which DNS server has the authority to set rDNS (PTR records)?

or to re-phrase... How to determine to whom authority has been delegated to set rDNS? Background In a multi-tier environment, where a block of IP's is assigned, then further split and assigned ...
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5answers
411 views

Is it good practice or too draconian to reject mails from mailservers with no RDNS

I've recently dropped SpamAssassin and am now basing spam rejection on DNSRBL's, grey-listing and other basic tests and I'm wondering whether I should also block hosts that don't have a valid RDNS ...
0
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1answer
113 views

Reverse dns for web/mail server with single ip

I have a single server with single ip running a web server, mail server and bind (all for a single domain). In my DNS zone file I created A records for www.domain.com, mail.domain.com, ns.domain.com ...
0
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1answer
193 views

Some E-mails are being rejected, do I need a DNS record for my default gateway?

I have been seeing more of these types of bounceback messages (IP address changed for example): mail.test.com #550-Your message was rejected by this user and was not delivered. 550-Reason: Your ...
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0answers
272 views

Mysql remote connections very slow - host lookups already disabled

I followed every instruction about this issue and nothing helped. Remote communication with MySQL server takes 4-30 seconds on simple query like select 1 from table_name and connection attempt often ...
0
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1answer
91 views

Reverse dns and SaaS Spam Filters

We have an exchange server in the office that for a year or so has just used the built-in spam filters - we have added the SpamHaus IP addresses so that some basic spam filtering is done. However, ...
1
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1answer
109 views

Reverse DNS lookup not resolving correctly

I've been searching and searching for the answer and I can't find it. My problem is that all of my emails sent from my server are either going to spam folders or not being delivered. I am trying to ...
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3answers
250 views

Are generic reverse DNS entries acceptable for an outgoing SMTP server?

Our PTR records are managed by our ISP, as our ranges are too small for them to consider delegating to us. So, every time I want to update an entry, I have to email their support team. In an effort ...
0
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1answer
58 views

rDNS entry on a separate name server from forward dns - is this okay?

Our reverse DNS lookup is delegated to our name server (ns.example1.com) by AT&T, who leases us our IP address (1.2.3.4) and our forward DNS lookups were on the same name server (ns.example1.com). ...
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2answers
387 views

delegating /24 and /64 reverse zones

I'm sure I'm overlooking something so simple, but I'm just not seeing it... I'm trying to delegate the /24 and /64 reverse zones for our Test network to hosts within the Test network. I'm seeing the ...
0
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1answer
118 views

rDNS setup to prevent emails appearing as spam / phishing messages

We are trying to send email without the email appearing in the spam folder. The emails that we are sending is solicited bulk email. The main problem is that the emails are appearing as phishing ...
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1answer
69 views

Domain names have gone down - site still up [closed]

I host a couple of websites on the same Ubuntu server, and as of today both domain names have gone down. PuTTY and FTP still both work so it is obviously a problem with the domain name. I haven't ...
0
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3answers
562 views

Does changing the Primary DNS Suffix of a Windows Server 2012 machine require a reboot?

My server has the following IP Addresses: 127.0.0.1 192.168.100.103 208.nnn.nnn.180 199.nnn.nnn.29 It's FQDN is mymachine.example.com. However, calling ...
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1answer
1k views

Cloudflare, reverse DNS and php mail ending up in spam folder

I've been using Cloudflare to host my DNS, and PHPMailer to send e-mail through ZOHOs SMTP servers with great success, but have found that all my e-mails are hitting Gmail, Zoho and Hotmails spam ...
0
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1answer
125 views

What is the structure of zones synthesized by BIND's empty-zones-enable feature?

BIND 9.4.1 implemented automatic empty reverse zones for private address space in order to prevent reverse DNS leakage. This saves an administrator the trouble of having to define these empty zones, ...
0
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1answer
130 views

Configuring bind with reverse DNS in external server

I'm having troubles configuring BIND with the reverse DNS being made by an external server in the hosting company. Lets assume i have a domain "server.com" that should contain 2 nameservers: ...
0
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1answer
164 views

SSH to a server with multiple reverse DNS entries [duplicate]

While SSHing into my server with an RSA key, I get this message: Address 255.100.236.105 1 maps to a1.example.com, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT! Even ...
0
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1answer
728 views

Reverse DNS and Godaddy email server, What should it point to?

We are assigned 3 static IP addresses by our ISP and lately we have been having problems delivering our mail. We checked with Cloudmark and they suggested contacting our ISP to add a reverse DNS entry ...
0
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3answers
96 views

Reverse dns returns a different host each time

So, randomly I happened to ping abc.com and found this fascinating: $ ping abc.com PING abc.com (199.181.132.250) 56(84) bytes of data. 64 bytes from m.abc.com (199.181.132.250): icmp_req=1 ttl=237 ...
3
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1answer
80 views

How do providers plan to deal with rDNS for client /64 IPv6 blocks when assigned?

The standard block assigned to a home will be a /64 block to enable autoconfigure. This means the traditional reverse DNS mapping of host-237.miami.ispname.com is not only practical, it's improbable ...
12
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1answer
507 views

How to force an ISP to remove false reverse DNS?

There is an IPv4 address (in a /8 managed by ARIN) that I have no control over which reverse resolves to a domain name which I registered. Someone used the IP address to run a scam, and it is ...
0
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1answer
122 views

Multi-IP server: how do programs know which IP to use?

I recently tried adding second IP address to our server for various reasons and found that now when I check netstat -anob there are many programs/services listening and establishing connections to ...
0
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1answer
95 views

Spam issue - outgoing mail server

Our previous developer wrote a basic aspx contact form for one of our hotel clients before leaving, all has been fine with it so far but when testing this week I noticed that although the email sent ...
0
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1answer
50 views

Mailserver DNS and rDNS setting

Let me start with the fact that things are quite weird in our organization. Now, we have to place a mailserver for a DNS zone that is under our control, for example xxx.yyy.zzz. However, we can't ...
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2answers
111 views

IPv6 reverse not resolving for Linux shell “last” and “who”

IPv6 is properly resolving in DNS: > host 2607:fa18:0:2::17 7.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.0.0.0.0.0.8.1.a.f.7.0.6.2.ip6.arpa \ domain name pointer sine.xmission.com. However, the ...
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1answer
121 views

Set up Reverse Delegation for Documentation Address in RFC 5737?

I am using CORE to develop some network emulations to teach some network concepts. One of those concepts is the correct setup of a recursive DNS server for local clients; an authoritative DNS server ...
3
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2answers
2k views

Disable reverse lookup in rsync daemon

I'm having an issue with some rsync modules being served through rsync --daemon This lines are from my /var/log/rsyncd.log file : 2013/02/08 12:15:28 [13174] name lookup failed for XXX.XXX.XXX.XXX: ...
0
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1answer
167 views

Cant see DNS zone Security properties or edit/ADD anything being a domain admin

We have a single domain in multiple forest environment. I tried to add a record to one of the reverse lookup zones of the domains which is a single domain in the single forest , i didnt have the ...
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2answers
209 views

Have issues in reverse lookup

I need assistance in a reverse lookup issue. I have a server say XYZ.ABC.COM having an IP 10.20.30.40. If I ping the server, it is resolving to the correct IP. On reverse ping (i.e ping -a ...
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1answer
53 views

Postfix sending emails via multiple broadband lines

I have a site that send out emails from a postfix server. They have multiple broadband lines for load balancing and failover. I want them to be able to send out emails though both lines without the ...
0
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1answer
108 views

Reverse DNS lookup doesn't match hostname

There's a service on our local intranet that depends on the hostname mapping to the ip address, it is failing for a centos host inside of a virtual machine. I have set the virtual network adapter as ...
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3answers
334 views

Ping hostname returns another hostname in output : what does it mean?

When I ping the server sip3.voip-centrex.net, I get this output: PING sip3.voip-centrex.net (194.98.81.144) 56(84) bytes of data. 64 bytes from mpfrrelay.michaelpage.fr (194.98.81.144): icmp_req=1 ...
0
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0answers
89 views

The email sent from my server are marked as spam

I have a dedicated server at OVH. For several days I've noticed I'm in a spam list (spamcannibal). The reason I said was for generic PTR. I've changed and I have commanded to remove from the list. ...
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2answers
3k views

How do I set up a reverse zone file?

I have this zone file in bind: $TTL 86400 mysite.net. IN SOA ns1.mysite.net. admin.mysite.net. ( 2006012008 86400 3600 604800 86400 ) ...
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2answers
499 views

Reverse DNS / PTR with Fasthosts shared hosting enviroment

I'm not that clued up on all aspects of DNS so apologies if this is a stupid question of sorts. Basically I have a VPS with one provider(Xeneurope) and the domain names with another(Fasthosts). Not ...
2
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1answer
1k views

Having trouble interpreting mail log DNS errors

I have a postfix mail server on Debian. A client of mine just informed me that they were unable to send an email to me and it appears that there is a problem with their mail server. I would like to ...
0
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1answer
67 views

Providing reverse records for records that map to ISP IP

I have been instructed to use my ISP ip (as a temporary fix for mapping my name server and domain records as my router dishes out rfc 1918 adresses to devices in my network where I am running an ...
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1answer
3k views

domain/IN: has no NS records

I have set up a home web server using Ubuntu 12.10 and I can safely say that it works with regards to router forwarding and ports being found. I know this, because switched my hosting provider's VPS ...
0
votes
1answer
117 views

Will PTR records for IP's that relay mail?

I am having some spam issues with my mail server. I have multiple servers that are relaying mail through my mail server. I am wanting to know if PTR records for these servers will have any effect ...
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2answers
166 views

How Reverse DNS does what it does

Hopefully this is not a stupid question, but I cannot find a clear cut answer. Can someone please inform me exactly what 'source address' is used in Reverse DNS? Does rDNS pull the IP address from ...
0
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1answer
164 views

how does domaintools.com perform it's reverse ip lookup?

I'm attempting to improve my understanding of the DNS system and am confused as to how domaintools.com manages to resolve all DNs associate with an IP addr. After playing around with dig, i'm stuck. ...
2
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2answers
827 views

What is the correct mail set up for multiple domains on one server?

I have a machine (centos 5) with one external ip address. On that machine I have many virtual hosts with a few different top level domain names and sub-domains under those eg. sub1.domain1.com ...
0
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1answer
87 views

Reverse DNS is finding someone else's domain

When I do a reverse DNS of my IP address I'm finding a different server name? This isn't my domain name. I was testing my mail server and it gave that warning. How do I fix it? $ nslookup Default ...
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2answers
2k views

How do I update my servers' domain name for Reverse DNS?

I'm updating my mail servers' rDNS and I think I have it all figured out except for one thing. When I installed my OS (Debian Etch), the installer asked me to enter the "domain name". Is the ...
0
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2answers
123 views

Reverse DNS Resolve for MX record

I've two servers running, one is a webserver and it's A record on my (external) DNS provider is in the form of: example.com in A XXX.XX.XXX.171 The other is a mailserver and it's A record is in the ...
2
votes
1answer
4k views

sshd warning, “POSSIBLE BREAK-IN ATTEMPT!” for failed reverse DNS

Whenever I SSH somewhere I get something like this in the logs: sshd[16734]: reverse mapping checking getaddrinfo for 1.2.3.4.crummyisp.net [1.2.3.4] failed - POSSIBLE BREAK-IN ATTEMPT! And it ...
0
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2answers
587 views

Creating reverse DNS entries which resolve [duplicate]

Possible Duplicate: Reverse DNS - how to correctly configure for SMTP delivery I ran a DNS check and ended up with the following error: FAIL: Found reverse DNS entries which don't resolves ...
0
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1answer
111 views

DNS setup: server1-> CNAME to server2 -> IP address without website being visible on server2

I've been trying to figure this out for a while. I've been googling but I couldn't really figure it out. I have bunch of VPS's for my clients. Each has its own IP address, with a single website on ...
0
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2answers
740 views

Reverse DNS for two ADs in the same subnet

I currently have two separate AD forests that exist within the same subnet. The two forests have independent copies of the reverse lookup zone for that subnet. Example: Domain A DC1: 10.1.1.1/24 ...