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Reverse PTR Zone

Paste an IP or a CIDR (IPv4 or IPv6 — auto-detected) and get the reverse name (in-addr.arpa / ip6.arpa) and a sample PTR zone block. Text manipulation only, no DNS queries.

Accepts IPv4 and IPv6, with or without a /prefix. Auto-detected.

{n} = host index · {ip} = IP · {last} = last octet / nibble. End with . (FQDN).

Examples
redzilla.cl — ptr 
 
  
 
 Family IPv4 
 
 Zone 1.168.192.in-addr.arpa  
 
 $ORIGIN 1.168.192.in-addr.arpa.  
 
  
 
 
PTR zone block
 
 —  
 
 
 
 
  
 
 How reverse DNS works 
 
 IPv4 The reverse name of
a.b.c.d is d.c.b.a.in-addr.arpa (octets
            reversed). For a /24 the zone is
c.b.a.in-addr.arpa and each host is a PTR
record.

 
 IPv6 The 32 nibbles are expanded, reversed
            and suffixed with .ip6.arpa. Each nibble (4 bits) is one
            label.

 
 /24 /16 /8 Only prefixes aligned to an octet
            (IPv4) or to a nibble multiple of 4 (IPv6) have a "clean" reverse zone.
            For /16 and /8 we show the zone and a
            template, not thousands of lines.

 
 RFC 2317 For IPv4 prefixes longer than
/24 (e.g. /27) classless delegation is used
            (CNAME); here we generate the range's PTR
records for reference.

 
 
 
 
 
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