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mx2.mail.plasa.com has one IP number , which also has a corresponding reverse pointer. plasa.com and telkom.net use this as a mailserver. Incoming mail for mail.plasa.com is handled by one mailserver having a total of two IP numbers. They are on the same IP network. mail.plasa.com has one IP number. mx2.mail.plasa.com is hosted on a server in Indonesia.

mx2.mail.plasa.com
a records
 
+ 222.124.18.72 222.124.18.0/24 AS17974 -
+ --- -

mail.plasa.com
a records
 
+ 202.134.0.30 202.134.0.0/24 AS17974  
+ ---  
mx records
in-mta2.plasa.com
+ 202.134.0.72 202.134.0.0/24 AS17974 -
+ --- -
+ 202.134.0.83 202.134.0.0/24 AS17974 -
ip numbers of host
222.124.18.72
ptrs of ip numbers
mx2.mail.plasa.com
ip numbers using ptr to this host
222.124.18.72
domains using this as mailserver
plasa.com
telkom.net