freebsd stable - Apr 2007 - Possible mtu bug in vlan or bce

Hi,

I have seen some strange behaviour today with VLAN interfaces on bce 
interfaces.  I am running 6.2 Release on i386.

I have a bce interface setup on a gig-e network with an MTU of 8192 i 
attach a vlan interface to this and chnage the vlan if mtu to 1500 as it 
has 100Mbit devices on it.  This does not seem to affect the MTU of the 
bce interface, the VLAN mtu is reported as changed by if config but the 
bce is not reported as changed.  However I then start to get error 
messages saying that the NFS server is not responding as it is sending 
packets larger than 1500 bytes.


If I try to raise the mtu of the vlan interface (to 8192 which is the 
value that ifconfig reports for bce0) at this stage ifconfig thows an 
error saying that the value is incorrect.  If I then 'raise' (it already
appears to be set to 8192 according to ifconfig) the mtu of bce0 to 8192 
and then set the vlan interface mtu to 8192 the nfs server starts to 
work again.


Is this a know bug/problem or should I raise a PR?

Thanks

Tom

Hi All,


Anyone tried new clamav version (Clamav  0.90.2) with 6.2 stable?. Also any
success using Clamav  0.90.1 without clamd.conf on 6.2?. Does it still need
lipthread mapping?

Cheers
Dim

At 04:21 PM 4/16/2007, Dimuthu Parussalla wrote:
>Anyone tried new clamav version (Clamav  0.90.2) with 6.2 stable?. Also any
>success using Clamav  0.90.1 without clamd.conf on 6.2?. Does it still need
>lipthread mapping?
Hi,
I am using .90.2 and have the lipthread mapping still.  Not sure if 
its needed or not, but its been running fine since Saturday.  Also, 
the box is RELENG_6, updated Saturday morning.  Remember, if you 
update to get the new sendmail in RELENG_6, make sure you recompile 
all your milters.

         ---Mike

On Tue, 17 Apr 2007 06:21:21 +1000
"Dimuthu Parussalla" <dparussalla@baysidegrp.com.au> wrote:
> Hi All,
> 
> 
> Anyone tried new clamav version (Clamav  0.90.2) with 6.2 stable?.
> Also any success using Clamav  0.90.1 without clamd.conf on 6.2?.
> Does it still need lipthread mapping?
> 
> Cheers
> Dim
Ok for me, compiled from source with 6.2 from Feb 11th.


-Adrian

Tom Judge wrote this message on Mon, Apr 16, 2007 at 18:21
+0100:
> I have seen some strange behaviour today with VLAN interfaces on bce 
> interfaces.  I am running 6.2 Release on i386.
> 
> I have a bce interface setup on a gig-e network with an MTU of 8192 i 
> attach a vlan interface to this and chnage the vlan if mtu to 1500 as it 
> has 100Mbit devices on it.  This does not seem to affect the MTU of the 
> bce interface, the VLAN mtu is reported as changed by if config but the 
> bce is not reported as changed.  However I then start to get error 
> messages saying that the NFS server is not responding as it is sending 
> packets larger than 1500 bytes.
> 
> 
> If I try to raise the mtu of the vlan interface (to 8192 which is the 
> value that ifconfig reports for bce0) at this stage ifconfig thows an 
> error saying that the value is incorrect.  If I then 'raise' (it
already
> appears to be set to 8192 according to ifconfig) the mtu of bce0 to 8192 
> and then set the vlan interface mtu to 8192 the nfs server starts to 
> work again.
Make sure that you change the host route's mtu down to the new MTU...
I changed the MTU behavior a while back so that you could have a mixed
network and support both large and regular sized MTU's on the same
nextwork...

# ifconfig em0
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 9000
        options=18b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWCSUM,TSO4>
        inet6 fe80::207:e9ff:fe0d:ad06%em0 prefixlen 64 scopeid 0x2 
        inet 192.168.0.21 netmask 0xffffff00 broadcast 192.168.0.255
        ether 00:07:e9:0d:ad:06
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
# netstat -rnWfinet
Routing tables

Internet:
Destination        Gateway            Flags    Refs      Use    Mtu    Netif
Expire
default            192.168.0.14       UGS         0     8024   1500      em0
[...]
192.168.0.18       00:c0:f0:42:23:87  UHLW        1        2   1500      em0  
1193
# route change 192.168.0.18 -mtu 9000
change host 192.168.0.18
# netstat -rnWfinet
Routing tables

Internet:
Destination        Gateway            Flags    Refs      Use    Mtu    Netif
Expire
[...]
192.168.0.18       00:c0:f0:42:23:87  UHLW        1        2   9000      em0  
1172
# ifconfig em0 mtu 1500
# ifconfig em0
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=18b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWCSUM,TSO4>
        inet6 fe80::207:e9ff:fe0d:ad06%em0 prefixlen 64 scopeid 0x2
        inet 192.168.0.21 netmask 0xffffff00 broadcast 192.168.0.255
        ether 00:07:e9:0d:ad:06
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
# netstat -rnWfinet
Routing tables

Internet:
Destination        Gateway            Flags    Refs      Use    Mtu    Netif
Expire
[..]
192.168.0.18       00:c0:f0:42:23:87  UHLW        1        2   9000      em0  
1128

Hmmm... We may want to add code that detects when the host route's MTU
is larger than the interface, and prevent that from happening.

Though if an mtu daemon ever gets written, then that should take care
of it.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."