Reverse DNS Lookup

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To look up the DNS record for your server, use the nslookup or host commands. Substitute your own email server information in the example,

Successful Reverse DNS Lookup

Terminal:~ user$ host 131.128.1.50
50.1.128.131.in-addr.arpa domain name pointer allies.uri.edu.
Terminal:~ user$ nslookup 131.128.1.50
50.1.128.131.in-addr.arpa name = allies.uri.edu.

Unsuccessful Reverse DNS Lookup

Terminal:~ user$ host 131.128.1.251
Host 251.1.128.131.in-addr.arpa not found: 3(NXDOMAIN)
Terminal:~ user$ nslookup 131.128.1.251
server can't find 251.1.128.131.in-addr.arpa: NXDOMAIN

If you need additional DNS records for your server(s), contact your Internet Service Provider. Call the ITS Help Desk at 401-874-HELP (4357) if you have questions or are not sure what to do.