The statement is false because, by default, when a BGP device advertises a route learned from an External BGP (EBGP) peer to an Internal BGP (IBGP) peer, it does not change the next-hop address. The next-hop attribute remains the IP address of the original EBGP peer. This behavior can cause reachability issues within the Autonomous System (AS) if internal routers do not have a route to the external next-hop. To resolve this, the peer next-hop-self command must be explicitly configured to change the next-hop to the advertising router's own address.

A. This is a true statement. When a BGP device originates a route locally (e.g., using the network command) and sends it to an IBGP peer, the next-hop is set to its own address.

C. This is a true statement. This is the standard and required behavior for EBGP. When advertising a route to an external peer, the next-hop is always updated to the IP address of the sending router's egress interface.

D. This is a true statement. To maintain a consistent view of the next-hop within an AS and prevent routing loops, the next-hop attribute is not changed when a route is passed from one IBGP peer to another.

1. Huawei HCIP-Datacom-Core Technology V1.0 Training Material:

In the chapter on BGP Path Attributes

the section discussing the NextHop attribute states: "When a BGP speaker advertises a route learned from an EBGP peer to an IBGP peer

it does not change the NextHop attribute of the route by default." This directly confirms that statement B is false. The same document also validates statements A

C

and D as correct default behaviors.

2. RFC 4271: A Border Gateway Protocol 4 (BGP-4):

Section 5.1.3

NEXTHOP: This section details the rules for setting the next-hop. It specifies that when advertising a route to an EBGP peer

the next-hop is the IP address of the advertising speaker (validating option C). It also states that when advertising a route learned from an EBGP peer to an IBGP peer

the advertising speaker does not modify the NEXTHOP attribute unless explicitly configured

which makes statement B incorrect.