Network & Connectivity

ASN Routing Issues

ASN (Autonomous System Number) routing issues involve problems with BGP (Border Gateway Protocol) route advertisements that affect how traffic flows between networks. Route leaks, hijacks, suboptimal paths, and missing announcements can cause connectivity loss, increased latency, or traffic interception.

Symptoms

  • Users in specific regions unable to reach your servers
  • Traffic taking inefficient paths, increasing latency
  • Intermittent connectivity issues correlated with BGP events
  • traceroute showing unexpected network paths

Common Causes

  • BGP route leak from a transit provider
  • BGP route hijacking by a malicious or misconfigured AS
  • Missing or withdrawn route announcements
  • Suboptimal BGP path selection due to missing peering
  • RPKI validation failures blocking legitimate routes

Step-by-Step Troubleshooting

  1. 1

    Look up ASN information

    Identify the ASN for the affected IP range and its upstream providers.

    Use ASN Lookup →
  2. 2

    Analyze IP reputation

    Check if the ASN or IP range has reputation issues.

    Use IP Analysis →
  3. 3

    Run traceroute

    Trace the network path to identify unexpected routing.

    Use Ping & Traceroute →
  4. 4

    Check ISP details

    Verify ISP information and connectivity.

    Use ISP Checker →
  5. 5

    Contact network provider

    Report the routing issue to your ISP or hosting provider with traceroute and BGP evidence.

Recommended Diagnostic Tools

ASN LookupIP AnalysisPing & TracerouteISP Checker

Monitor Network Routes

Track routing changes and detect ASN-level issues.

Related Problems

Frequently Asked Questions