Hi,

Today something strange happened on one of my Soekris 5501 boxes,
it runs OpenBSD 4.1-stable. The box is connected with a cross-over cable 
to another machine via the vr1 interface (the box has 4 vr interfaces).

Problem: After having rebooted the machine at the other end of the cable 
multiple times, the Soekris box suddenly stopped receiving packets on 
the vr1 interface.

After playing around with ping and tcpdump on both sides I found out
that the vr1 interface allowed me to send packets, but incoming packets 
did no show up in tcpdump, even though the LED on the interface was 
flickering.

I changed the cable, connected the vr1 of the Soekris to another 
machine, then to a switch port with lots of broadcast traffic etc.etc. 
nothing helped, ingress traffic on vr1 did not show up in tcpdump.

Solution: Finally, immediatelly after doing "ifconfig vr1 down && 
ifconfig vr1 up" everything worked again as normal.

The link on vr1 is currently only used to do SSH between the two 
machines, so this is really a low traffic link. On the other hand, 
vr0,vr2,vr3 are heavily used (BGP sessions etc., the Soekris is at the 
border of my AS). btw: the machine at the other end of the cable is a 
Soekris 5501 as well. Had to reboot it to perform a BIOS upgrade.

No suspicious output in dmesg.

Any ideas on how I could further track down the problem?

Thanks,
  Christian

The vr interfaces in dmesg:

vr0 at pci0 dev 6 function 0 "VIA VT6105M RhineIII" rev 0x96: irq 11, 
address 00:00:24:c8:de:68
ukphy0 at vr0 phy 1: Generic IEEE 802.3u media interface, rev. 3: OUI 
0x004063, model 0x0034
vr1 at pci0 dev 7 function 0 "VIA VT6105M RhineIII" rev 0x96: irq 5, 
address 00:00:24:c8:de:69
ukphy1 at vr1 phy 1: Generic IEEE 802.3u media interface, rev. 3: OUI 
0x004063, model 0x0034
vr2 at pci0 dev 8 function 0 "VIA VT6105M RhineIII" rev 0x96: irq 9, 
address 00:00:24:c8:de:6a
ukphy2 at vr2 phy 1: Generic IEEE 802.3u media interface, rev. 3: OUI 
0x004063, model 0x0034
vr3 at pci0 dev 9 function 0 "VIA VT6105M RhineIII" rev 0x96: irq 12, 
address 00:00:24:c8:de:6b
ukphy3 at vr3 phy 1: Generic IEEE 802.3u media interface, rev. 3: OUI 
0x004063, model 0x0034

# ifconfig vr1 

vr1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
         lladdr 00:00:24:c8:de:69
         media: Ethernet autoselect (100baseTX full-duplex)
         status: active
         inet XX.XX.XX.XX netmask 0xffffffe0 broadcast XX.XX.XX.YY
         inet6 fe80::200:24ff:fec8:de69%vr1 prefixlen 64 scopeid 0x2