Re: [Xen-users] crc checksum problems

[Renà Pfeiffer <lynx@xxxxxxxxx>]

On Jan 16, 2006 at 2136 -0600, Daniel Goertzen appeared and said:
> I observed similar problems (checksum errors) when I directly assigned 
> an IP address to the bridge in dom0.

My bridges have IP addresses, but the addresses are not used. Could this
be a problem?

> I corrected the situation by adding vif0.0 to the bridge and assigning
> the IP address to veth0.  If you're using the network-bridge script
> that comes with xend this all happens automatically, but I had to roll
> my own solution and ran afoul.

I use xend's network-bridge script and have additional network
interfaces defined in /etc/network/interfaces. The bridges look as
follows:

xen0:~# brctl show
bridge name     bridge id               STP enabled     interfaces
xenbr0          8000.feffffffffff       no              peth0
                                                        vif0.0
                                                        vif19.0
xenbr1          8000.dabb912575c8       no              dummy1
                                                        vif14.0
                                                        vif19.1
xen0:~# 

peth0 and vif0.0 are from Dom0. vif19.0 and vif19.1 belong to the
firewall in the first DomU and the vif14.0 belongs to the webserver.
dummy1 is one of two dummy interfaces. A /29 network is routed to the
machine. Dom0 has the first address, eth0 inside the firewall's DomU has
the second, both use the gateway serving the /29. Neither peth0 nor
vif0.0 have IP addresses configured. 

My assumption was that the first bridge xenbr0 forwards the packets to
the gateway. ICMP, TCP SYN and even TCP SYN plus data works, everything
else won't.

Maybe someone can explain the background of the checksum errors.

Best regards,
Lynx.

-- 
"From the delicate strands,
 between minds we weave our mesh:
 a blanket to warm the soul."
 --- Lady Deirdre Skye (SMAC) ---


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