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IPv4: Preise, Regeln, Praxis
Leitfäden vom Team, das den Adressraum vermietet, kauft und verkauft: was ein Block wert ist, was Sie vor der Übernahme prüfen sollten, wann Mieten besser ist als Kaufen und wie die Reputation eines Blocks sauber bleibt.
Unsere Artikel erscheinen auf Englisch.
IPv6 for your own network: PI, PA or a lease?
IPv6 is not scarce, so the question is whose addresses they are. PI through a sponsoring LIR, PA as an LIR, or a lease: what each allows, and which fits.
Leasing or buying IPv4: how the numbers actually compare
Lease or buy is usually framed as capital against cost. What decides it is the block: PA needs LIR membership, and PI cannot go to your customers.
Is the RIPE NCC waiting list worth it? Running the numbers
Queueing for a RIPE NCC /24 means paying membership while you wait, and since September 2026 extra LIR accounts are restricted. When the math still works.
Legacy IPv4 space: what it is and why buyers pay more for it
Legacy blocks were handed out before the RIRs existed and sit under lighter rules than allocated space. What that means for buyers and holders.
IPv4 exhaustion: what it means for your business in 2026
The registries have all but run out of IPv4, and it is not coming back. That makes it a procurement decision: three routes, each with a price and a lead time.
How leasing IPv4 works, from first message to live addresses
What happens between asking for a /24 and announcing it: the quote, the contract, the registry work behind the LOA and the ROA, and what changes at renewal.
GRE tunnels for IPv4: when you need one and how to set it up
A tunnel brings IP addresses to a server that cannot announce them: no BYOIP at your provider, no ASN, or fewer than 256 addresses. GRE or WireGuard, and MTU.
IP reputation: how to keep an IP block clean
A block that routes perfectly can still be useless if it is listed. What a listing breaks, why addresses get listed, and how to find out first and stay off.
The real cost of public IPv4 in AWS, Azure and Google Cloud
Every major cloud bills public IPv4 by the hour. What that adds up to over a year, and how bringing your own space changes the arithmetic.
How much is my IPv4 block worth?
Price per address is not a single number. Six factors decide what a block actually fetches, and two of them can make an otherwise good block unsellable.
RPKI and ROAs: what buyers and lessees actually need to do
Large networks drop routes that fail RPKI validation. What a ROA is, who creates it, why no ROA beats a wrong one, and what ASPA adds.
Do you need your own AS number?
You need an AS number to make your own routing decisions, not to use IP addresses. When you need one, when you do not, and a proposed RIPE policy change.
What an IPv4 lease contract should contain
A lease is only as good as its contract. The ten things to read before you sign: the block, renewal, when it can be taken back, price changes, listings and law.
What a sponsoring LIR is, and when you need one
PI space and AS numbers need a contract, but not a membership of your own. What a sponsoring LIR does, what it costs, and when you need your own LIR.
Reverse DNS for leased IP space: PTR records, delegation and mail
Who controls the PTR records of leased addresses, how reverse DNS is delegated, and the forward-confirmed match that Gmail and other mail receivers check.
The letter of authorization (LOA): what it is and who signs it
An LOA is the holder's written permission for a network to announce its addresses. What it contains, who asks for one, and how it differs from a ROA.
IRR route objects and RADb: why a prefix gets filtered
A valid ROA is not enough if your upstream builds its filters from routing registries. What a route object is, where it lives, and how to check it.
How to check an IP block before you buy or lease it
A block can arrive listed, hijacked or registered to a company that no longer exists. Seven checks with public tools to run before you sign, and the commands.
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