http://www.dnsstuff.com/ is your friend! Generally reverse DNS is governed by your ISP. This quick extract from a reverse DNS lookup should explain it: Preparation: The reverse DNS entry for an IP is found by reversing the IP, adding it to "in-addr.arpa", and looking up the PTR record. So, the reverse DNS entry for 67.19.87.202 is found by looking up the PTR record for 202.87.19.67.in-addr.arpa. All DNS requests start by asking the root servers, and they let us know what to do next. See How Reverse DNS Lookups Work for more information. How I am searching: Asking b.root-servers.net for 202.87.19.67.in-addr.arpa PTR record: b.root-servers.net says to go to dill.arin.net. (zone: 67.in-addr.arpa.) Asking dill.arin.net. for 202.87.19.67.in-addr.arpa PTR record: dill.arin.net [192.35.51.32] says to go to NS1.THEPLANET.COM. (zone: 19.67.in-addr.arpa.) Asking NS1.THEPLANET.COM. for 202.87.19.67.in-addr.arpa PTR record: Reports core.networksaremadeofstring.co.uk. [from 207.44.128.228] Answer: 67.19.87.202 PTR record: core.networksaremadeofstring.co.uk. [TTL 86400s] [A=67.19.87.202] Now when I am searching the other way it is YOUR DNS server that answers the queries: How I am searching: Searching for core.networksaremadeofstring.co.uk A record at h.root-servers.net [128.63.2.53]: Got referral to ns1.nic.uk. (zone: uk.) [took 49 ms] Searching for core.networksaremadeofstring.co.uk A record at ns1.nic.uk. [195.66.240.130]: Got referral to ns2.networksaremadeofstring.co.uk. (zone: networksaremadeofstring.co.uk.) [took 125 ms] Searching for core.networksaremadeofstring.co.uk A record at ns2.networksaremadeofstring.co.uk. [67.19.87.203]: Reports core.networksaremadeofstring.co.uk. [took 44 ms] Response: Domain Type Class TTL Answer core.networksaremadeofstring.co.uk. A IN 14400 67.19.87.202 networksaremadeofstring.co.uk. NS IN 14400 ns2.networksaremadeofstring.co.uk. networksaremadeofstring.co.uk. NS IN 14400 ns1.networksaremadeofstring.co.uk. ns1.networksaremadeofstring.co.uk. A IN 14400 67.19.87.202 ns2.networksaremadeofstring.co.uk. A IN 14400 67.19.87.203 -----Original Message----- From: redhat-list-bounces@xxxxxxxxxx [mailto:redhat-list-bounces@xxxxxxxxxx] On Behalf Of sylvan dacounha Sent: 11 May 2007 09:37 To: General Red Hat Linux discussion list Subject: query regarding reverse IP Dear All, I am new to DNS concepts.. and sorry for this silly query i have a query regarding reverse IP and apprecite if someone could help me... I have a redhat 9 with bind bind-9.2.1-9 i have a DNS server running on xx.xx.xx.1 IP and this DNS server has one domain example.com . I also have a mailserver running on the same IP for the example.com domain and is working fine . and also the ISP has the reverse IP setup for the above domain that is abc.example.com now i am also using the same DNS server to host another domain example1.com and is workin fine. I also have recently configured a mail server for the example1.com domain and the mail server is running on another machine that is xx.xx.xx.2 now i see that when i send mail to servers like hotmail n gmail the mail goes to junk mail folder rather than to inbox but when i send mail from my first domain that is example.com it goes fine now when i do a reverse for my xx.xx.xx.1 IP it gives me example.com but when i do a reverse for my xx.xx.xx.2 IP it cannot find the example1.com domain. now i want to know if the reverse lookup can be done locally in my DNS or the ISP. and if the ISP has to do it which IP for my example1.com domain i have to give. IS it xx.xx.xx.2 ???? also if i have a third domain configured on the same DNS server and a mailserver running on 3rd machine whould i also give the 3rd IP of the mail server to do a reverse to my ISP appreciate ur help thnks and regards --------------------------------- Get the free Yahoo! toolbar and rest assured with the added security of spyware protection. -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
