diff --git a/libraries/io/eth/eth.peripheral.yaml b/libraries/io/eth/eth.peripheral.yaml
index b887db31986ab67e390213cd6b06844e5147cedb..083ec80cfba988b8619e5670e503529677c8e853 100644
--- a/libraries/io/eth/eth.peripheral.yaml
+++ b/libraries/io/eth/eth.peripheral.yaml
@@ -233,5 +233,48 @@ peripherals:
number_of_fields: 1024 # = c_eth_ram_nof_words in eth_pkg.vhd
access_mode: RO
-
-
+ - peripheral_name: eth_tester_offload_hdr_dat
+ peripheral_description: "UDP offload header for the eth tester [1]."
+ mm_ports:
+ # MM port for eth_tester.vhd / dp_offload_tx_v3.vhd
+ - mm_port_name: REG_DP_OFFLOAD_TX_HDR_DAT
+ mm_port_type: REG
+ mm_port_span: 32 * MM_BUS_SIZE
+ mm_port_description: |
+ "The ETH/IP/UDP/application header fields for the 1GbE eth_tester offload UDP packets.
+
+ The RO value reads the MM value, not the used data path value. Therefore simply use access
+ mode RW for all fields. Whether the write RW MM value is used in the packet header depends
+ on the c_eth_tester_hdr_field_sel bit selection setting in eth_tester_pkg.vhd.
+
+ [1] https://support.astron.nl/confluence/display/L2M/L6+FWLIB+Design+Document%3A+ETH+tester+unit+for+1GbE
+ "
+ fields:
+ # eth field group
+ - - { field_name: word_align, mm_width: 16, access_mode: RW, address_offset: 0x64 }
+ - - { field_name: eth_destination_mac, mm_width: 32, user_width: 48, radix: uint64, access_mode: RW, address_offset: 0x5c }
+ - - { field_name: eth_source_mac, mm_width: 32, user_width: 48, radix: uint64, access_mode: RW, address_offset: 0x54 }
+ - - { field_name: eth_type, mm_width: 16, access_mode: RW, address_offset: 0x50 }
+ # ip field group
+ - - { field_name: ip_version, mm_width: 4, access_mode: RW, address_offset: 0x4c }
+ - - { field_name: ip_header_length, mm_width: 4, access_mode: RW, address_offset: 0x48 }
+ - - { field_name: ip_services, mm_width: 8, access_mode: RW, address_offset: 0x44 }
+ - - { field_name: ip_total_length, mm_width: 16, access_mode: RW, address_offset: 0x40 }
+ - - { field_name: ip_identification, mm_width: 16, access_mode: RW, address_offset: 0x3c }
+ - - { field_name: ip_flags, mm_width: 3, access_mode: RW, address_offset: 0x38 }
+ - - { field_name: ip_fragment_offset, mm_width: 13, access_mode: RW, address_offset: 0x34 }
+ - - { field_name: ip_time_to_live, mm_width: 8, access_mode: RW, address_offset: 0x30 }
+ - - { field_name: ip_protocol, mm_width: 8, access_mode: RW, address_offset: 0x2c }
+ - - { field_name: ip_header_checksum, mm_width: 16, access_mode: RW, address_offset: 0x28 }
+ - - { field_name: ip_source_address, mm_width: 32, access_mode: RW, address_offset: 0x24 }
+ - - { field_name: ip_destination_address, mm_width: 32, access_mode: RW, address_offset: 0x20 }
+ # udp field group
+ - - { field_name: udp_source_port, mm_width: 16, access_mode: RW, address_offset: 0x1c }
+ - - { field_name: udp_destination_port, mm_width: 16, access_mode: RW, address_offset: 0x18 }
+ - - { field_name: udp_length, mm_width: 16, access_mode: RW, address_offset: 0x14 }
+ - - { field_name: udp_checksum, mm_width: 16, access_mode: RW, address_offset: 0x10 }
+ # application field group
+ - - { field_name: dp_reserved, mm_width: 31, access_mode: RW, address_offset: 0xC }
+ - - { field_name: dp_sync, mm_width: 1, access_mode: RW, address_offset: 0x8 }
+ - - { field_name: dp_bsn, mm_width: 32, user_width: 64, radix: uint64, access_mode: RW, address_offset: 0x0 }
+