ASN stands for Autonomous System Number. It is a unique identifier assigned to an autonomous system (AS) in the Internet that participates in the Border Gateway Protocol (BGP). An autonomous system is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators that has a single, clearly defined routing policy.
In practical terms, an ASN is used by routers in the Internet to exchange information about IP routing paths. Each AS has a unique ASN, which is used to identify it to other ASes and to BGP routers in the Internet. This enables routers to determine the best path for traffic to take as it travels between different ASes and across the Internet.
ASNs are assigned by the Internet Assigned Numbers Authority (IANA) to regional Internet registries, which in turn allocate them to individual organizations or Internet Service Providers (ISPs) that operate autonomous systems.
The Letter of Authorization (LOA) is a formal document issued to a client after successfully completing the Assignment Request process. This document grants the client permission to announce an ASN (Autonomous System Number) for a specified IP address range.
The LOA serves as proof that the client has the right to broadcast and manage the assigned IP address range within a network. It is often required by data centers, internet service providers, and network operators to confirm that the client is authorized to use the specified resources.
The document typically includes the following details:
This document ensures proper routing and compliance within global network infrastructures, preventing unauthorized use of IP address space.
The Assignment Request (AR) process is initiated by the customer after successfully completing an order to rent an IP block. Other participants in the process include the supplier of the IP block (from whom the customer placed the order) and the InterLIR nanager.
The outcome of the process is that the customer can announce an ASN on the IP block using an LOA (Letter of Authorization) and utilize the rented block in accordance with the signed contract and the rules governing the use of the rented resource.
You can read the rental rules in the General Terms and Conditions for the Use of the Internet Site interlir.com section.
Reverse DNS (rDNS) is the process of resolving an IP address to a domain name, the opposite of the standard DNS lookup. In a regular DNS query, a domain name is translated into an IP address. However, with rDNS, the system identifies which domain name is associated with a specific IP address.
rDNS is primarily used for verification and security purposes. It helps validate the origin of emails to reduce spam by confirming that the sender’s IP address matches a legitimate domain name. Many mail servers reject or flag emails from servers without proper rDNS configuration.
rDNS records are stored as PTR (Pointer) records in the DNS database. Unlike forward DNS, rDNS queries use a special domain called in-addr.arpa, where the IP address is reversed and appended with this domain for lookup.
Setting up rDNS requires administrative access to the DNS records of the IP address block. It is typically managed by the IP block owner or provider through cooperation with the relevant Regional Internet Registry (RIR), such as RIPE for Europe.
Although rDNS is not essential for most internet services, it plays a key role in improving trust and reducing network abuse.
You can make a rDNS Request to the leased IP-Block to connect rDNS.
tech-c: The technical contact responsible for the technical operations and management of the resource.
admin-c: The administrative contact responsible for organizational decisions and resource management.
CIDR (Classless Inter-Domain Routing) is a method for allocating and representing IP addresses and their associated routing. CIDR uses the format:
IP_address/prefix_length, where:IP_address is the starting address of the range.prefix_length is the prefix, which specifies the number of bits used for the network portion of the address.The prefix represents the number of leading 1 bits in the IP Block mask. It determines the width (in bits) of the IP Block.
A “route” is an object in an RIR (Regional Internet Registry) database that ties an IP block (inetnum/inet6num) to a specific ASN (Autonomous System Number), thereby authorizing that ASN to announce the block.
RPKI (Resource Public Key Infrastructure) is a cryptographic system that ties IP blocks and ASN (Autonomous System Number) to digital certificates, allowing networks to verify that a given ASN is legitimately authorized to announce a particular prefix.
Hijacking is the announcement of an IP block without the consent of the resource holder.
An “inetnum” (internet number) is an object in an RIR (Regional Internet Registry) database that records the details of an IP block allocation or assignment.
RIR (Regional Internet Registry) is an organization that oversees the allocation and registration of IP address space and ASN (Autonomous System Number) within a defined region.
LIR (Local Internet Registry) is a member of an RIR (Regional Internet Registry). An LIR distributes IP addresses to end users and/or uses them in its own infrastructure.
An “org” (organisation) is an object in an RIR (Regional Internet Registry) database that provides information about an organisation that has allocation or assignment of an internet resource (IP block/ASN).
Abuse-c (abuse contact) is an object in an RIR (Regional Internet Registry) database that provides contact information for handling reports of network abuse.
Subnet status is an attribute in an IP block object (inetnum/inet6num) that indicates how a specific IP block is being used or managed. The main statuses are as follows:
LEGACY: IP address space was assigned before the current RIR system was established. An LIR can make assignments or sub-allocations from this allocation.
ALLOCATED PA (Provider Aggregatable): IP address space has been allocated to an LIR by an RIR. An LIR can make assignments or sub-allocations from this allocation.
SUB-ALLOCATED PA (Provider Aggregatable): IP address space that the LIR has been sub-allocated to another organization for reassignment.
ASSIGNED PA (Provider Aggregatable): IP address space has been assigned to an end user by an LIR. It can’t be further assigned.
ASSIGNED PI (Provider Independent): IP address space has been assigned by the RIR directly to an end user for a specific purpose. It can’t be further assigned.
Blacklists are databases of IP addresses, domains, or ASNs that have been observed sending spam, malware, or other abusive traffic. Mail servers and security appliances query these lists to decide whether to block or flag incoming connections. The main blacklists are maintained by Spamhaus Project, Barracuda Central, and SpamCop.
MNT-BY is a top-level maintainer that allows you to edit information in inetnums (whois), create any lower-level objects such as route, rDNS, inetnums, and create and edit route, rDNS on the same level as MNT-BY.
MNT-DOMAIN is a maintainer that allows you to create and edit information in rDNS (domain objects).
WHOIS is a publicly accessible protocol and database used to look up registration information about internet resources such as IP addresses, AS numbers, and domain names.
WHOIS is essential for network troubleshooting, abuse reporting, and verifying resource ownership. Data is maintained by Regional Internet Registries (RIRs) and domain registrars.
ROA stands for Route Origin Authorization — a cryptographically signed object in the RPKI system that authorizes a specific Autonomous System (AS) to originate a particular IP prefix in BGP.
ROAs are used by routers and validators to determine if BGP announcements are valid, helping to prevent route leaks and hijacks.
A ROA might state:
“AS64500 is authorized to announce 192.0.2.0/24 with max length /24.”
Without a matching ROA, a route may be marked as Invalid during RPKI validation.
IANA (Internet Assigned Numbers Authority) is the organisation that registers IP addresses and top-level domains. It reports directly to ICANN and in particular is responsible for allocating addresses to RIRs.
RIR (Regional Internet Registry) manages the allocation of IP addresses (IPv4 and IPv6), AS number and registration of LIRs in a particular region of the world. There are 5 main RIRs in the world – RIPE, ARIN, APNIC, LACNIC, AFRINIC.
IPv4 transfer is the procedure by which the rights to IPv4 addresses are transferred from one user to another. The outcome of this process is the updating of RIR databases and the designation of the transferee by the resource’s owner (user). Transfers can occur as a result of the sale or purchase of addresses or through the merger of companies and assets. The legal and procedural aspects of transfers vary depending on the type of addresses (see What is subnet status) and the rules of the RIRs involved in the transfer process.
Resource Transfer Agreement (TA, Transfer Agreement) is the document whose signing is required under RIPE NCC rules to carry out an address transfer procedure. This document is signed by both parties to the transfer (the transferrer and the transferee) and submitted to RIPE NCC, after which the registrar records the change of address ownership in the database. In other Regional Internet Registries, transfer procedures typically do not require the signing of such agreements.
APNIC is the Regional Internet Registry (RIR) responsible for allocating and registering Internet number resources—like IP addresses—to organizations across 56 economies in the Asia Pacific region. To better serve specific areas, APNIC sometimes works with National Internet Registries (NIRs), which operate under APNIC policies to handle local allocations and registrations in the community’s native language. There are currently seven such NIRs, each dedicated to supporting its own regional Internet community: APJII (Indonesia), CNNIC (China), IRINN (India), JPNIC (Japan), KISA (Korea), TWNIC (Taiwan) and VNNIC (Vietnam).
IPv4 (Internet Protocol version 4) is the fourth version of the Internet Protocol responsible for addressing and routing most of today’s Internet traffic. It uses 32-bit addresses (for example, 192.0.2.1), which allows for a total of 2³² = 4,294,967,296 possible addresses.
Such limitations lead to a shortage of available addresses and make them highly sought after in the rental and sale markets.
The usage type of an IP address refers to the intended purpose or environment in which the IP address is used. It helps classify how and where an IP is typically deployed, and is useful for security analysis, network management, geolocation services, and IP reputation systems.
Understanding the usage type helps in assessing the trustworthiness and behavior of an IP address, particularly for fraud detection, ad targeting, and cybersecurity analysis.
The most expensive in terms of leasing IP addresses belong to the ISP usage type. Providers and proxy services want their IPs to be classified as ISP to appear more like legitimate end-user traffic. ISP-tagged IPs are less likely to be blocked, rate-limited, or flagged by anti-bot and fraud detection systems. This improves access to websites, APIs, and services that restrict data center or proxy IPs. It also helps avoid CAPTCHAs, login challenges, and bans. Streaming platforms, e-commerce sites, and financial services often deny access from non-ISP IPs. ISP-tagged IPs are more trusted and offer better compatibility with consumer-facing platforms. For proxy services, this classification increases the resale value of IPs by marketing them as “residential.” It also helps bypass geo-restrictions and web application firewalls. Essentially, the ISP label gives the impression of real human users. That’s why it’s strategically important for traffic quality, reputation, and business success.
A VPN (Virtual Private Network) is a technology that creates a secure, encrypted connection over a less secure network—typically the Internet. It is widely used for privacy, security, and remote access. When you use a VPN, your device connects to a VPN server via a secure tunnel. This tunnel encrypts all the data transmitted between your device and the server, making it unreadable to third parties like hackers, ISPs, or even government agencies.
Cloud refers to cloud computing, which is the delivery of computing services—such as servers, storage, databases, networking, software, analytics, and intelligence—over the Internet (“the cloud”). Instead of owning and maintaining physical data centers or servers, individuals and companies can access technology services on demand from cloud providers.
A proxy server is an intermediary between your device and the internet. It receives your request, forwards it to the target server, and sends the response back to you. Its main function is to hide your IP address and increase anonymity. Proxies are often used to bypass content blocks and geo-restrictions. They can also filter web traffic and cache data to improve speed. Common types include forward, reverse, anonymous, and transparent proxies. Transparent proxies do not hide their use. Unlike a VPN, a proxy typically does not encrypt your data. It usually works at the application level, like in a browser. Proxies are useful, but VPNs offer stronger security and privacy.
Hosting is a service that allows individuals or organizations to make their websites accessible on the Internet. A hosting provider stores your website files on a server connected to the web. When someone types your domain name, the hosting server delivers the website content to their browser. There are different types of hosting: shared, VPS, dedicated, and cloud hosting. Shared hosting means multiple websites share the same server resources. VPS hosting offers more control and resources by dividing a server into virtual machines. Dedicated hosting gives you an entire server for your website only. Cloud hosting uses multiple servers for higher reliability and scalability. Good hosting ensures fast loading times, security, and minimal downtime. Choosing the right hosting depends on your website’s size, traffic, and technical needs.
A data center is a facility that houses computer systems and related components, such as servers, storage, and networking equipment. It is designed to store, manage, and distribute large amounts of data. Data centers provide critical infrastructure for websites, cloud services, and enterprise applications. They include power supplies, cooling systems, and security measures to ensure continuous operation. There are different types: enterprise, colocation, cloud, and edge data centers. Enterprise data centers are owned by a single company, while colocation centers host equipment for multiple clients. Cloud data centers support services like AWS, Google Cloud, and Azure. Edge data centers are located closer to users for faster processing. Data centers must be reliable, secure, and energy-efficient. They are essential for modern digital communication and business operations.
A domain is the unique name used to identify a website on the Internet. It serves as a human-readable address, like example.com, instead of a numerical IP address. Domains are made up of two main parts: the name (e.g., “google”) and the extension (e.g., “.com”). They must be registered through domain registrars such as GoDaddy or Namecheap. Domains point to a server where the website files are hosted. When you type a domain into a browser, the Domain Name System (DNS) translates it into an IP address. There are different types of domains: top-level domains (TLDs), like .com or .org, and country-specific ones, like .uk or .de. Subdomains (like blog.example.com) are used to organize content. Owning a domain gives you control over branding and online presence. Domains are essential for websites, email addresses, and many online services.
A VPS (Virtual Private Server) is a virtualized server that acts like a dedicated server within a shared hosting environment. It uses virtualization technology to divide a physical server into multiple isolated virtual servers. Each VPS has its own operating system, storage, CPU, and RAM. Users have root access and can install software or configure settings independently. VPS offers more control, flexibility, and performance than shared hosting. It’s ideal for websites or applications that need more resources or security. While cheaper than a dedicated server, a VPS still provides a high level of reliability. It can be used for hosting websites, game servers, development environments, and more. VPS hosting can be managed (provider handles maintenance) or unmanaged (user handles everything). It’s a popular choice for growing businesses and tech-savvy users.
Evgeny Sevastyanov
Support Team Leader
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