Hi! The server Dell PowerEdge R640 (baseboard 0PHYDR) with BIOS Version: 1.6.13 02/13/2019 [Hetzner 1.0.2] has Intel 1GB i350 network card: igb0@pci0:1:0:0: class=0x020000 card=0x1f9a1028 chip=0x15218086 rev=0x01 hdr=0x00 vendor = 'Intel Corporation' device = 'I350 Gigabit Network Connection' class = network subclass = ethernet It runs FreeBSD 11.2-STABLE/amd64 r344922 with GENERIC kernel config plus following options only: options KDB options KDB_UNATTENDED options KDB_TRACE options DDB options GDB It also runs ipfw nat that is not compatible with TSO4 so this option is disabled for igb0. Still, running with tso4 disabled and txcsum enabled, it suffers from stalled TCP connections due to some TCP segments being sent with broken checksum occasionally. ifconfig igb0 -txcsum solves the problem.
(In reply to Eugene Grosbein from comment #0) Are you able to retest with 12.2 or 13.0?
(In reply to Kevin Bowling from comment #1) Unfortunately, no as this server is in production and it's owner will not justify an upgrade while it works fine with work-around.
I suspect this is fixed in 12+ by code inspection; I've looked intently at the txrx in these newer versions of the driver and don't see any issues. Please reopen if you see otherwise in the future.