CyberGuard dictionary / Network Security
BGP Routing
Border Gateway Protocol is the routing protocol used by autonomous systems to exchange reachability information across the Internet.
In simple terms
Large networks use BGP to tell neighboring networks which IP prefixes they can reach.
Technical explanation
BGP speakers advertise routes and apply policy to select and propagate paths. Incorrect or unauthorized announcements can misroute traffic; operators use filtering and routing security controls to reduce this risk.
BGP exchanges route announcements between autonomous systems. Incorrect or malicious announcements can redirect or blackhole traffic, so operators use route filters and available validation mechanisms.
Examples in practice
An internet provider announces a customer prefix to peers so traffic for that address range can reach the customer network.
A provider mistakenly announces a route for a network it does not own, and some visitors reach the wrong path. Operators withdraw the announcement and check route monitoring for the affected interval.
Why it matters
Routing mistakes can affect availability and traffic paths far beyond one organization's firewall.
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Sources and further reading
Published 2026-10-15 · Last updated 2026-10-15 · CyberGuard editorial content. Source links provide context; they do not imply endorsement.