RTSAK FAQ - Frequently Asked Questions

RTSAK (Route Tools Swiss Army Knife) is a free BGP and routing analysis tool. We provide AS lookups, BGP route analysis, and prefix origin validation for network operators and security researchers.

Yes. All routing analysis tools are free with no registration required.

Network operators, NOC teams, security researchers, and anyone investigating internet routing - peering decisions, troubleshooting connectivity, detecting prefix hijacks, or understanding traffic paths.

BGP routing tables update continuously. Our data reflects recent routing state, though propagation delays mean changes take minutes to appear globally.

An AS is a network or group of networks under single administrative control that presents a common routing policy to the internet. Each AS has a unique AS Number (ASN).

Look up any IP address your organization controls in AS Lookup — the results show the announcing ASN. Alternatively, check your allocation records with your regional internet registry (ARIN, RIPE, APNIC, LACNIC, or AFRINIC).

Transit is a paid service where one network carries another's traffic to the entire internet. Peering is a mutual exchange of customer traffic between two networks, typically settlement-free. Understanding this distinction is key to reading AS relationship data in AS Lookup.

The AS may be dormant (allocated but not actively routing), used purely for internal purposes, or in the process of transitioning. Some ASNs are held in reserve. Check AS Lookup for the AS's registration details even when no routes are visible.

Yes. Large organizations often operate several ASNs for different business units, geographic regions, or technical purposes (e.g., acquisition of other companies).

Border Gateway Protocol is how networks share reachability information. When your network announces a prefix, that advertisement propagates globally, telling other networks how to reach your addresses.

Prepending artificially lengthens the AS path by repeating your ASN, making that route less preferred by other networks. It's a common traffic engineering technique to shift inbound traffic toward alternate links. View prepending in action through BGP Routes.

BGP is a distributed protocol — each network applies its own routing policies independently. The path from AS A to your network will differ from the path AS B takes. This is normal and expected. BGP Routes shows paths from our vantage points.

Route flapping occurs when a route is repeatedly withdrawn and re-announced, usually due to an unstable link. Persistent flapping can trigger route dampening by other networks, temporarily making your prefix unreachable even when the link is up. Monitor route stability through BGP Routes.

Most changes reach global visibility within minutes. However, route dampening, filtering policies, and complex peering arrangements can slow propagation for specific prefixes or paths.

When the same prefix is announced by multiple ASNs. This isn't always malicious - legitimate scenarios include anycast, authorized co-hosting, and transitions.

A Route Origin Authorization is a cryptographically signed statement declaring which AS is authorized to announce a specific prefix. ROAs are the strongest available form of origin validation, allowing networks to filter bogus announcements. Check prefix validation status in Prefix Origin.

If you hold a direct allocation from a regional internet registry, create ROAs through your RIR's portal (ARIN, RIPE, APNIC, LACNIC, or AFRINIC). For provider-assigned address space, coordinate with your upstream provider. Verify your ROA status using Prefix Origin.

Networks that implement RPKI route origin validation may drop or deprioritize invalid routes. Adoption is growing but not yet universal, so some networks still accept invalid announcements. Check the current validation state of any prefix in Prefix Origin.

Contact the RIR responsible for the prefix, notify your upstream transit providers, and reach out to the legitimate prefix owner if identifiable. Gather evidence from BGP Routes and Prefix Origin showing the unauthorized origin AS.

A /24 is 256 IP addresses. Larger prefixes (like /16 = 65,536 IPs) are more aggregated. Many networks filter prefixes smaller than /24 in IPv4 to limit routing table size.

Tags attached to routes that affect how other networks treat them. Used for traffic engineering, blackholing, and policy signaling between networks.

Checking whether the AS announcing a prefix is authorized to do so, using IRR records, RPKI ROAs, or RIR allocation data.

A facility where multiple networks connect to exchange traffic directly rather than through transit providers. IXPs improve latency, reduce costs, and increase redundancy. --- Need to analyze routing? Try AS Lookup, BGP Routes, or Prefix Origin on rtsak.com.