New TrueNAS Community build, unable to set mtu = 9000 on TX401

I have installed TrueNAS 25.10.1 - Goldeye on a very old motherboard with AMD Phenom processor, 8 G RAM running on Kingston SSD drive. The NIC is a TrendNet TX-401 10 GB NIC in a PCIe 3 slot. Surprisingly it is performing on par with my QNAP NAS.

My question is, I am trying to set up jumbo frames on the NIC, but every time I try to,I loose connectivity to the NAS. I have used this NIC previously on the same switch with 9000 mtu without issue. The only difference it was in a much newer Windows 11 computer, not Linux. I have read several posts with people using jumbo frames on TX401, so I am wondering what could be the issue here?

The system has loaded the following driver for the card.

truenas_admin@truenas[~]$ ethtool -i enp1s0
driver: atlantic
version: 6.12.33-production+truenas
firmware-version: 3.1.121
expansion-rom-version:
bus-info: 0000:01:00.0
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: yes
supports-priv-flags: yes

ethtool listing

Settings for enp1s0:
Supported ports: [ TP ]
Supported link modes: 100baseT/Full
1000baseT/Full
10000baseT/Full
2500baseT/Full
5000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 100baseT/Full
1000baseT/Full
10000baseT/Full
2500baseT/Full
5000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: 2500Mb/s
Duplex: Full
Auto-negotiation: on
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
MDI-X: Unknown
Supports Wake-on: pg
Wake-on: g
Current message level: 0x00000005 (5)
drv link
Link detected: yes

Is there a better driver I should be using or related to using the NIC on an very old motherboard?

Success!!!

I changed the MTU to 8972 instead of 9000 after reading how Linux requires reducing the mtu size by 28 bytes as it needs the reduction to account for the overhead. :slight_smile:

1 Like