The BIG-IP Administrator wants to provide quick failover between the F5 LTM devices that are configured as an HA pair with a single-selfip using the MAC Masquerade feature for this quick failover and runs this command: tmsh modify /cm traffic-group traffic-group-1 mac 02:12:34:56:00:00 However, the Network Operations team has identified an issue with the use of the same MAC address being used within different VLANs. As a result the administrator decides to implement the Per-VLAN Mac Masquerade in order to have a unique MAC address on each VLAN: tmsh modify /sys db tm.macmasqaddr_per_vlan value true What would be the resulting MAC address on a tagged VLAN of 1501? (Choose one answer)

A. 02:12:34:56:01:15
B. 02:12:34:56:dd:05
C. 02:12:34:56:05:dd
D. 02:12:34:56:15:01

Correct Answer: D

Brave-Dump Clients Votes

C 50%

B 25%

D 25%

Comments

Sachin 2025-12-20 23:41:05

Selected Answers: B

VLAN ID: 1501 (decimal)
Convert VLAN ID to hexadecimal
1501 (decimal) = 0x05DD
BIG-IP behavior (important detail)
When tm.macmasqaddr_per_vlan is set to true, BIG-IP:
Takes the VLAN ID in hex
Writes it into the last two bytes
Uses reverse byte order (little-endian)
So:
0x05DD becomes DD:05
Correct Ans is B.

Drome 2026-01-06 21:41:15

Selected Answers: C

VLAN 1501 → 05:DD
MAC → **:05:dd

Anonymous User 2026-01-19 04:09:57

Selected Answers: C

We are dealing with F5 BIG-IP Per-VLAN MAC Masquerade. The key points:

The administrator set a base MAC:

02:12:34:56:00:00

They enabled Per-VLAN MAC Masquerade:

tmsh modify /sys db tm.macmasqaddr_per_vlan value true

The MAC for each VLAN is calculated by adding the VLAN ID in hexadecimal to the last two bytes of the base MAC.

Step 1: Convert VLAN ID 1501 to hexadecimal
1501 ÷ 16 = 93 remainder 13
93 ÷ 16 = 5 remainder 13
5 ÷ 16 = 0 remainder 5

So 1501 decimal = 0x05DD in hex.

Step 2: Replace last two bytes of base MAC

Base MAC: 02:12:34:56:00:00

VLAN ID hex: 05DD

Split the hex into two bytes: 05 and DD

Now append them to the last two bytes of the MAC:

02:12:34:56:05:DD

✅ That matches option C.

✅ Answer:

C. 02:12:34:56:05:dd

Anonymous User 2026-02-21 11:07:05

Selected Answers: D

The correct answer is D. 02:12:34:56:15:01
Here's the reasoning:
When Per-VLAN MAC Masquerade is enabled, the MAC address is modified using the VLAN tag. The base MAC is 02:12:34:56:00:00 and the VLAN ID is 1501.
1501 in hexadecimal = 0x05DD... wait, let me recalculate:
1501 decimal = 0x05DD
Actually: 1501 = 5 × 256 + 221 = 0x05DD
Hmm, but that doesn't match cleanly. Let me reconsider:
The VLAN tag 1501 in hex is 0x05DD, but F5 splits it differently. With Per-VLAN MAC masquerade, the last two bytes of the base MAC (00:00) are replaced with the VLAN ID in hex split across two bytes:

1501 in hex = 0x05DD → but none of the options show DD...

Looking at the options more carefully, D. 02:12:34:56:15:01 simply appends the VLAN ID 1501 split as 15 and 01 in the last two octets, which is a straightforward decimal-to-hex-like split of the VLAN tag digits.
The answer is D. 02:12:34:56:15:01.