On Friday May 13 2005 6:58 pm, Monique Y. Mudama wrote: > "Does your mail server have a PTR entry in your DNS zone file? [...] > ... but that doesn't make sense to me. I have different A and MX > records for the domain, specifically so that I can use a hosted web > service while serving mail on a different machine. If that weren't > perfectly legit, why even have the concept of an MX record? Well, a PTR is a PoinTeR record. Here's some examples from my internal domain, network.ursine.ca, as well as it's reverse lookup zone, 0.168.0.in-addr.arpa (before dynamic updates make it unreadable): $ORIGIN . $TTL 600 ; 10 minutes network.ursine.ca IN SOA ursine.ca. hostmaster.ursine.ca. ( 2005051305 ; serial 600 ; refresh (10 minutes) 600 ; retry (10 minutes) 2419200 ; expire (4 weeks) 600 ; minimum (10 minutes) ) NS ursine.ca. $ORIGIN network.ursine.ca. broadcast A 192.168.0.255 TXT "Broadcast address" network A 192.168.0.0 TXT "Network address" and the reverse zone... $ORIGIN . $TTL 600 ; 10 minutes 0.168.192.in-addr.arpa IN SOA ursine.ca. hostmaster.ursine.ca. ( 2005051305 ; serial 1200 ; refresh (20 minutes) 600 ; retry (10 minutes) 2419200 ; expire (4 weeks) 1200 ; minimum (20 minutes) ) NS ursine.ca. $ORIGIN 0.168.192.in-addr.arpa. 0 PTR network.ursine.ca. 1 PTR gateway.ursine.ca. 255 PTR broadcast.ursine.ca. The reverse zone is what gets you to the point where you can do this: baloo@ursine:~$ host 192.168.0.255 255.0.168.192.in-addr.arpa domain name pointer broadcast.ursine.ca. You need to create a reverse zone for your network. -- Paul Johnson Email and Instant Messenger (Jabber): baloo@ursine.ca http://ursine.ca/~baloo/
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