Weird network interface configuration in FreeBSD 9.0?

Question

FreeBSD

Good afternoon!

# uname -sr
FreeBSD 9.0-RELEASE-p4

# ifconfig em0 inet 92.xx.xx.xx netmask 255.255.255.248 mtu 5000 -wol && /etc/netstart

# ifconfig em0 |grep media

media: Ethernet autoselect (100baseTX <full-duplex>)

At the same time, wget downloads from the Internet at a speed of about 8 MiB per second - everything is fine. But if you do it like this:

# ifconfig em0 inet 92.xx.xx.xx netmask 255.255.255.248 media 100baseTX mediaopt full-duplex mtu 5000 -wol && /etc/netstart

# ifconfig em0 |grep media
media: Ethernet 100baseTX <full-duplex>
Then after that wget downloads from the same address (and from any others) a maximum of 0.1 MiB per second. With the same, it would seem, settings.
CHADNT?

Answer 1

the first thing that came to mind was that autonegotiate is turned off and the hardware on the other side sets the wrong duplex. if possible, look at the number of collisions and late collisions.

Answer 2

Faced similar on Hetzner's servers. Only the complete shutdown of auto negotiation and the manual installation of media and duplex helped.
The fact is that they disable 1000TX on the switches, and this causes some chips (realtek) to lose logic and they switch to 100TX / half-duplex and this is not treated with auto negotiation enabled. Try turning it off, it might help.

Answer 3

Mediaot was last used in RTComm on a 10 megabit link. It still made sense. Yes, leave auto, the days of crooked network hardware are long gone, even long lines are not mistaken with duplexes when autodetect at 100 Mbps =)
Why do you need mtu 5000? Jumbo frames are actually 9000, and they work in one segment (they won’t go outside, the router will cut into standard pieces), but with modern network cards with LSO and queues, they have long lost their meaning.