Which of the following about default BGP behavior is FALSE?

Question

Options

• ANext Hop is modified in iBGP updates.
• BOrigin Code is NOT modified in eBGP updates.
• CAS Path is modified in eBGP updates.
• DLocal Preference is NOT modified in iBGP updates.

• A
  74% (20)
• B
  7% (2)
• C
  4% (1)
• D
  15% (4)

Explanation

Option A is the false statement because, by default, BGP does not modify the Next Hop attribute in iBGP updates - the Next Hop remains set to the eBGP neighbor's address that originally advertised the route, which is why "Next Hop Self" is often needed to ensure internal peers can actually reach that next hop.

Options B, C, and D are all true statements and therefore wrong answers for this question:

• B is true: Origin Code travels unchanged through eBGP - routers don't alter how a route was originally introduced into BGP.
• C is true: AS Path is modified in eBGP - each eBGP speaker prepends its own AS number before advertising, which is how loop prevention works.
• D is true: Local Preference is an iBGP-only attribute and passes between iBGP peers unmodified; it isn't even sent to eBGP peers.

Memory tip: Think "eBGP stamps, iBGP passes." eBGP stamps its AS onto the AS Path and sets a new Next Hop - iBGP just passes attributes along untouched, including Next Hop and Local Preference.

No community discussion yet for this question.