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ns3.hamburgsud.com has one IP number , which also has a corresponding reverse pointer. hamburgsud.com is a domain controlled by two nameservers at hamburgsud.com themselves. They are on different IP networks. Incoming mail for hamburgsud.com is handled by two mailservers also at hamburgsud.com. They are on different IP networks. ns3.hamburgsud.com is hosted on a server in Germany.

ns3.hamburgsud.com
a records
 
+ 212.48.111.90 212.48.96.0/19 AS8893 -
+ --- -

hamburgsud.com
ns-soa records
ns4.hamburgsud.com
+ 62.44.32.166 62.44.32.0/23 AS41707  
+ ---  
ns records
ns4.hamburgsud.com
+ 62.44.32.166 62.44.32.0/23 AS41707  
+ ---  
ns5.hamburgsud.com
+ 212.72.167.3 212.72.160.0/19 AS8893 -
+ --- -
mx records
smtpham01.hamburgsud.com
+ 217.6.170.199 217.0.0.0/13 AS3320  
+ ---  
smtpham02.hamburgsud.com
+ 62.44.32.173 62.44.32.0/23 AS41707  
ip numbers of host
212.48.111.90
ptrs of ip numbers
ns3.hamburgsud.com
ip numbers using ptr to this host
212.48.111.90