go
mx.vtr.net has one IP number , but the reverse is pc-24-1-83-200.cm.vtr.net. pc-24-1-83-200.cm.vtr.net point to the same IP. vtr.net is a domain controlled by two nameservers at vtr.net themselves. They are on different IP networks. Incoming mail for vtr.net is handled by one mailserver at cgp.vtr.net. vtr.net has one IP number. mx.vtr.net is hosted on a server in Chile.

mx.vtr.net
a records
 
+ 200.83.1.24 200.83.0.0/23 AS22047 pc-24-1-83-200.cm.vtr.net
+ --- pc-24-1-83-200.cm.vtr.net

vtr.net
a records
 
+ 200.83.4.60 200.83.0.0/19 AS22047  
+ ---  
ns-soa records
ns00.vtr.net
+ 200.104.255.130 200.104.248.0/21 AS22047 -
+ --- -
ns records
ns00.vtr.net
+ 200.104.255.130 200.104.248.0/21 AS22047 -
+ --- -
ns01.vtr.net
+ 200.74.121.200 200.74.121.0/24 AS22047 -
mx records
mx.cgp.vtr.net
+ 200.83.2.212 200.83.2.0/24 AS22047 -
+ --- -
ip numbers of host
200.83.1.24
ptrs of ip numbers
pc-24-1-83-200.cm.vtr.net
hostnames sharing ip with a-records
pc-24-1-83-200.cm.vtr.net