NICs: Intel Corporation Ethernet Controller X710 for 10GbE SFP+ (rev 01) Kernel: 3.10.0-1062.18.1.el7.x86_64 DPDK Version: dpdk-20.11-rc5 My setup looks like below. 1st Machine 2nd Machine +-------------------------+ +------+ +-------------------------+ | +---------+ +-------+| | | +-------+ | | | tcpdump |---| NIC A |-------| ------|NIC A |---------+ | | +---------+ +-------+| | | +-------+ | | | | | | | +----|----+ | | | |Switch| | | Testpmd | | | - | | | | +---------+ | | +---------+ +-------+| | | +-------+ | | | | ptp4l |---| NIC B |-------| ------| NIC B |---------+ | | +---------+ +-------+| | | +-------+ | +-------------------------+ +------+ +-------------------------+ I use ptp4l to generate the PTP sync messages using the command ptp4l -i eno4 -2 -m -H The Testpmd is compiled using meson -Dc_args="-DRTE_LIBRTE_IEEE1588" build and run with commands ./app/dpdk-testpmd -l 1,2,3 -- -i --nb-cores=2 --coremask=0xc --forward-mode=ieee1588 testpmd> start In testpmd I have modified the app/test-pmd/ieee1588fwd.c, such that the PTP SYNC messages are forwarded to the NIC A of the first machine by hardcoding the destination mac address. In NIC A of the first machine. I dump the packets received from testpmd, where I do not find the timestamps added. The tcpdump logs output 13:57:59.793588 e4:43:4b:5e:27:83 (oui Unknown) > e4:43:4b:5e:1c:22 (oui Unknown), ethertype Unknown (0x88f7), length 60: 0x0000: 0002 002c 0000 0200 0000 0000 0000 0000 ...,............ 0x0010: 0000 0000 e443 4bff fe5e 1c23 0001 2a14 .....CK..^.#..*. 0x0020: 0000 0000 0000 0000 0000 0000 0000 .............. 13:57:59.793609 e4:43:4b:5e:27:82 (oui Unknown) > e4:43:4b:5e:1c:22 (oui Unknown), ethertype Unknown (0x88f7), length 60: 0x0000: 0002 002c 0000 0200 0000 0000 0000 0000 ...,............ 0x0010: 0000 0000 e443 4bff fe5e 1c23 0001 2a14 .....CK..^.#..*. 0x0020: 0000 0000 0000 0000 0000 0000 0000 ... I would like to understand why I am not seeing the PTP sync packets timestamped by hardware. Is there anything I need to change in my setup to get the hardware timestamping working ? Also the PTP sync packet generated by ptp4l is also not timestamped, while the PTP follow up message is timestamped. However the testpmd handles only PTP sync packets