vlan issues with 7.0-RC3

Pyun YongHyeon pyunyh at gmail.com
Fri Feb 29 06:04:00 UTC 2008


On Wed, Feb 27, 2008 at 06:38:40PM -0800, Christopher Cowart wrote:
 > On Tue, Feb 26, 2008 at 04:43:55PM +0900, Pyun YongHyeon wrote:
 > >On Mon, Feb 25, 2008 at 01:17:12AM -0800, Christopher Cowart wrote:
 > >> Hello,
 > >> 
 > >> I have a mac mini running 7.0-RC3, which I'm trying to turn it into a
 > >> router. I have a Linksys SRW2008 "fully managed" (via an IE only web
 > >> interface, ick) switch. 
 > >> 
 > >> Switch:
 > >>   Port 1 - Trunk vlans 10,60,98 - FreeBSD Box
 > >>   Port 7 - Access vlan 98 - Existing LAN (192.168.1.0/24)
 > >> 
 > >> OpenWRT (192.168.1.1):
 > >>   WRT54G box on the Existing LAN
 > >> 
 > >> FreeBSD Box:
 > >>   ifconfig msk0 up
 > >>   ifconfig vlan98 create vlan 98 vlandev msk0 inet 192.168.1.67/24
 > >> 
 > >> With this configuration, I can ping hosts on the other lan segment (Port
 > >> 7). Arp and icmp seem to be quite happy. Unfortunately, I'm not having
 > >> any luck with tcp and udp. Any attempt to ssh to OpenWRT or dig
 > >> @OpenWRT hangs indefinitely. If I do a tcpdump, I see the SYN or A?
 > >> leaving and absolutely no response returning. If I run a tcpdump on
 > >> OpenWRT, I see no incoming traffic.
 > >> 
 > >> When I try to connect *to* the FreeBSD box from the other lan segment, I
 > >> continue to have problems. tcpdump shows the SYNs arriving via vlan98
 > >> and the FreeBSD box responding with SYN-ACK. OpenWRT receives the SYNACK.
 > >> 
 > >> I disabled ipfw just to be sure (sysctl -w net.inet.ip.fw.enable=0), but
 > >> it had no effect on the problem. If I connect the FreeBSD box to a vlan
 > >> 98 access port and assign the address to msk0, my connectivity problems
 > >> go away. This leads me to believe that the firewall on OpenWRT is not
 > >> the problem and the problem is related to vlans.
 > >> 
 > >> Thinking it was a problem with the not-so-cheap Linksys POS (bitterness
 > >> about the IE web interface again), I plugged my MacBook (running
 > >> Leopard, not FreeBSD) into the trunk port. Running the ifconfig commands
 > >> above (s/msk0/en0/), I got up and running without any problems. This
 > >> causes me to suspect the FreeBSD box.
 > >> 
 > >> Does anyone have any idea what's going on here? Any suggestions for
 > >> further troubleshooting?
 > >> 
 > >
 > > Try disabling hardware features one by one in msk(4) and see how
 > > it goes.
 > >  o Disable TSO.
 > >  o Disable Tx checksum offload.
 > >  o Disable VLAN hardware tagging.
 > 
 > Works great after `sudo ifconfig msk0 -txcsum'. 
 > 
 > Is this a known bug, or should I file a PR? Let me know if there are any
 > other details I can provide to help somebody squash it.
 > 

Would you capture broken TCP/UDP frames with tcpdump on receiving side
and show it to me?

-- 
Regards,
Pyun YongHyeon


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