H12-821_V1.0 · Question #334
BGP uses TCP as the transport layer protocol, so what is the TCP port number used by BGP?
The correct answer is A. 179. BGP (Border Gateway Protocol) is assigned TCP port 179 by IANA, and this is a fixed, well-known port that all BGP implementations use to establish and maintain peer sessions. Port 80 is HTTP, used for unencrypted web traffic and has no relation to routing protocols. Port 249 is…
Question
Options
- A179
- B80
- C249
- D182
How the community answered
(26 responses)- A77% (20)
- B12% (3)
- C8% (2)
- D4% (1)
Explanation
BGP (Border Gateway Protocol) is assigned TCP port 179 by IANA, and this is a fixed, well-known port that all BGP implementations use to establish and maintain peer sessions. Port 80 is HTTP, used for unencrypted web traffic and has no relation to routing protocols. Port 249 is not assigned to any major well-known protocol and is simply a distractor. Port 182 is similarly not associated with BGP or any commonly tested protocol.
Memory tip: BGP was standardized in RFC 1771 (later updated by RFC 4271), and 179 is close to 1771 reversed and shortened - but a simpler trick is to remember "BGP = 179" the same way you remember "HTTP = 80" and "HTTPS = 443": just drill the trio of routing protocol ports (BGP 179, OSPF uses IP directly, EIGRP uses IP 88) as a group.
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