When you subnet for example the ip what if there is someone that owns the ip address ? My confusion comes from the fact that I dont know how IANA, RIPE and the others give IPs. Do they only give class C addresses or if they give class B how are they making sure that there isn't someone else that might be using an IP address in the range that they gave away ?

1 Answer 1


Once more: Clasful networking is dead Please don't use Class-A, B, C, D, E outside the correct historical context.

IP address distribution works like this:

IANA -> RIR (e.g. RIPE) -> LIR (Provider) -> Customer 
IANA -> RIR (e.g. RIPE) -> Customer (PI) 

RIR: Regional Internet Registry (ARIN, ARIN, APNIC, LANIC, AfriNIC)

LIR: Local Internet Registry

PI: Provider Independent

Currently RIPE only hands out /22 networks to new members or existing members (if they ask for one). This will work as long as they have free networks left.You can't get IPv4 PI from RIPE anymore.

When you provider gives you a network he has to take care that there are no overlaps and collisions with other customer (or internal) networks. So if you provider is doing is job you can subnet your networks as you like, there will be no overlaps with other customers.

  • One more thing. If I get and someone has isn't that still a collision ? I mean if i want my server to be at how would the computer know where to go ? Sep 11, 2015 at 8:33
  • is a host address not a network address. As is Just the netmasks are different. is part of So if nobody makes a mistake there are no collisions.
    – user2084
    Sep 11, 2015 at 8:44

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