Network traffic from a Mellanox NIC appears to be leaving the system but never makes it to the wire

Solution Verified - Updated -


  • Packets leaving the transmission queue (TX) in route to port 2049 on Red Hat Enterprise Linux 6 appear to never actually leave the NIC and make it to the wire.
  • One particular service (eg: NFS, SSH, DNS, or NTP) fails or stops responding but other network traffic works fine, and restarting the service makes it start working again.
  • Having intermittent network issues on servers running RHEL with a Mellanox network card or mlx4 driver


  • Red Hat Enterprise Linux 5.10 or earlier
  • Red Hat Enterprise Linux 6.5 or earlier
  • Red Hat Enterprise MRG 2.5 or earlier
  • Mellanox Technologies ethernet controller using mlx4_en driver

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