350-401 Question 152
Select 2An enterprise network engineer is tasked with configuring eBGP between two directly connected routers, R1 and R2. The BGP configuration is as follows on R1:
router bgp 65001
neighbor 192.168.1.2 remote-as 65002
neighbor 192.168.1.2 password cisco123
After the initial configuration, the BGP session does not establish. Upon inspection, the engineer verifies that the interface connecting R1 and R2 is operational, the IP addressing is correct, and there is full Layer 3 reachability. Which of the following steps can resolve the issue and establish the BGP session?
- A
Ensure that the same password is configured on R2 for the BGP neighbor relationship
- B
Remove the
passwordstatement from the BGP configuration on R1 - C
Verify that the AS number on R2 matches the
remote-asconfigured on R1 - D
Enable the
ebgp-multihopfeature for the neighbor relationship - E
Configure the
update-sourceparameter to use the loopback interface on both routers
Show answer and explanation
Correct answers: A, C
Explanation
To establish an eBGP session between directly connected neighbors, the BGP configuration must meet specific requirements. First, the AS number on each router must match the respective neighbor's remote-as configuration. Second, if a BGP password is configured on one router, it must also be configured on the other router with the same value. In this scenario, ensuring the correct password and AS number resolves the configuration issue without requiring additional features like ebgp-multihop or update-source.
- A. Correct.
The BGP password must match on both neighbors for the session to establish. If the password is missing or mismatched, the session will not come up.
- B. Incorrect.
Removing the password is not recommended because the configuration explicitly includes the password. Removing it would not align with the given requirements.
- C. Correct.
If the AS number on R2 does not match the
remote-asconfigured on R1, the BGP session will not establish because the AS numbers must align for eBGP. - D. Incorrect.
The
ebgp-multihopfeature is unnecessary in this scenario since the neighbors are directly connected. This feature is used for non-directly connected eBGP peers. - E. Incorrect.
The
update-sourceparameter is not needed here as the neighbors are directly connected. This parameter is used when eBGP neighbors communicate via loopback interfaces.