Bug ID 755296: tcpdump does not capture packets from Mellanox VFs when DPDK is in use

Last Modified: Jul 12, 2023

Affected Product(s):
BIG-IP All(all modules)

Known Affected Versions:
15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4

Opened: Jan 11, 2019

Severity: 5-Cosmetic

Symptoms

On BIG-IP, if a Mellanox virtual function is used along with DPDK, an 'ethX' device is present as a Linux device. Attempts to attach to this with tcpdump do not result in any packets being captured.

Impact

Confusion when a device is observed in Linux and an attempt is made to capture on it. In most cases, before attaching to a device the tmm causes the kernel module to detach from it, which removes the 'ethX' device. However, due to an implementation detail of the Mellanox DPDK support, this is not possible for these NICs.

Conditions

-- BIG-IP Virtual Edition (VE) with a Mellanox virtual function and DPDK selected as the driver. -- Specify the kernel interface (ethX) rather than the tmm's interface (1.X) when running tcpdump.

Workaround

Run tcpdump against the tmm interface (1.1, 1.2, etc) that corresponds to the device in question rather the kernel interface. This allows capture of the desired packets.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips