BGP Routes - Real-Time Routing Table Analysis

Examine BGP routing data to understand how traffic flows across the internet. BGP route lookup shows the paths networks advertise, helping operators troubleshoot connectivity issues and verify routing configuration.

How BGP Routing Works

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

BGP routes include:

• Prefix - The IP address block being announced
• AS path - The sequence of networks the announcement traversed
• Origin - Whether the prefix is originated by the announcing AS or learned
• Communities - Tags affecting how other networks treat the route
• Next hop - The immediate destination for traffic to this prefix

Route Lookup Applications

Verify announcements - Confirm your prefixes are visible globally and through expected paths. Misconfiguration can cause partial reachability.

Detect hijacks - Unauthorized announcements create conflicting routes. Route lookup shows all origins advertising a prefix.

Path debugging - When traffic takes unexpected paths, examine AS paths to understand routing decisions.

Change validation - After BGP configuration changes, verify routes appear as intended before and after.

Understanding Route Data

The AS path tells the story of how a route propagated. Your prefix might show different paths from different vantage points - this is normal BGP behavior, not an error.

Route origin validation (RPKI) adds security. Lookup results indicate whether routes are RPKI-valid, invalid, or unknown, helping identify potentially suspicious announcements.

Multiple origins for the same prefix (MOAS) isn't always malicious - legitimate scenarios include anycast, authorized co-hosting, and transitions. Context determines whether MOAS indicates a problem.

→ Check BGP routes

FAQ

What does AS path prepending do? Adding your ASN multiple times to the path makes that route less preferred. It's used to influence inbound traffic engineering.

Why do I see different AS paths from different locations? BGP routing is distributed. Each network makes independent decisions, so paths vary by vantage point. This is normal.

What causes route flapping? Unstable links cause rapid route withdrawals and re-announcements. Persistent flapping may trigger route dampening by other networks.

How quickly do BGP changes propagate? Most changes propagate globally within minutes. Complex situations involving dampening or filtering may take longer.