Hi,
I would like to run a network firewall as a VM on a KVM host. There are
~ 25 VLANs delivered to the KVM host on three dedicated links, no LACP
or other things. I have the VLANs 100-180 on the host's enp1s0, the VLANs
200-280 on the host's enp2s0 and the VLANs 300-380 on the host's enp3s0.
To save myself from configuring all VLANs on the KVM host, I'd like to
hand the entire ethernet link to the VM and to have the VLAN interfaces
there. Using classical Linux bridges (brctl), things work fine.
They don't when I try macvlan:
On the host:
4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP mode DEFAULT group default qlen 1000
link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff promiscuity 1 addrgenmode
eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
5: unt382@enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP mode DEFAULT group default qlen 1000
link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff promiscuity 0
vlan protocol 802.1Q id 382 <REORDER_HDR> addrgenmode eui64
numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
15: macvtap3@enp3s0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500
qdisc pfifo_fast state UP mode DEFAULT group default qlen 500
link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0
macvtap mode bridge addrgenmode eui64 numtxqueues 1 numrxqueues 1
gso_max_size 65536 gso_max_segs 65535
4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff
inet6 fe80::20d:b9ff:fe34:2afe/64 scope link
valid_lft forever preferred_lft forever
5: unt382@enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP group default qlen 1000
link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff
inet6 fe80::20d:b9ff:fe34:2afe/64 scope link
valid_lft forever preferred_lft forever
15: macvtap3@enp3s0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500
qdisc pfifo_fast state UP group default qlen 500
link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff
inet6 fe80::5054:ff:febf:bbab/64 scope link
valid_lft forever preferred_lft forever
In the XML:
<interface type='direct'>
<mac address='52:54:00:bf:bb:ab'/>
<source dev='enp3s0' mode='bridge'/>
<target dev='macvtap3'/>
<model type='virtio'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
</interface>
And in the VM:
root@grml ~ # ip -d link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode
DEFAULT group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0
addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs
65535
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state
UP mode DEFAULT group default qlen 1000
link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 addrgenmode
eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
3: vlan0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP mode DEFAULT group default qlen 1000
link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0
vlan protocol 802.1Q id 382 <REORDER_HDR> addrgenmode eui64
numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
root@grml ~ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state
UP group default qlen 1000
link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff
inet6 fe80::5054:ff:febf:bbab/64 scope link
valid_lft forever preferred_lft forever
3: vlan0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP group default qlen 1000
link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff
inet 192.168.252.220/24 brd 192.168.252.255 scope global vlan0
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:febf:bbab/64 scope link
valid_lft forever preferred_lft forever
root@grml ~ #
I then ping from the VM to 192.168.252.241, which is a differnt host on
the network, neither the VM host the VM is running on nor another VM on
the same host. That should rule out the connectivity issues that a
macvtap interface has, right? On the VM, I see ARP requests going out,
but no answers come in.
On the pinged host, I see:
22:50:23.881163 52:54:00:bf:bb:ab > ff:ff:ff:ff:ff:ff, ethertype ARP
(0x0806), length 60: Request who-has 192.168.252.241 tell 192.168.252.220,
length 46
22:50:23.881242 52:54:00:95:df:a6 > 52:54:00:bf:bb:ab, ethertype ARP
(0x0806), length 42: Reply 192.168.252.241 is-at 52:54:00:95:df:a6, length 28
So, the packets going out from my VM are correctly delivered to the
target, the target replies, but the replies never make it back to the
VM.
Do I see correctly that tcpdump on the VM host won't give accurate
readings since macvtap will divert the frame before tcpdump will see it?
On the other hand, a VM directly configured to the host's unt382
interface works fine:
<interface type='direct'>
<mac address='52:54:00:cb:ed:34'/>
<source dev='unt382' mode='bridge'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
</interface>
I would however like to avoid having 25 interface stanzas in my XML.
I would appeciate any ideas to solve this issue. I know this is most
probably not a libvirt issue, but this list is about the only place that
comes to my mind where people knowledgeable about those complex network
stuff might hang around. If there is a better place to ask, I am open
for suggestion. Please pardon my intrusion.
Greetings
Marc
--
-----------------------------------------------------------------------------
Marc Haber | "I don't trust Computers. They | Mailadresse im
Header
Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402
Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421
Hi, nobody? If this is the wrong forum, where can I find people who can help with this issue? Greetings Marc On Sun, Dec 16, 2018 at 10:59:22PM +0100, Marc Haber wrote:> From: Marc Haber <mh+libvirt-users@zugschlus.de> > Subject: macvtap and tagged VLANs to the VM > To: libvirt-users@redhat.com > Date: Sun, 16 Dec 2018 22:59:22 +0100 > User-Agent: Mutt/1.9.5 (2018-04-13) > > Hi, > > I would like to run a network firewall as a VM on a KVM host. There are > ~ 25 VLANs delivered to the KVM host on three dedicated links, no LACP > or other things. I have the VLANs 100-180 on the host's enp1s0, the VLANs > 200-280 on the host's enp2s0 and the VLANs 300-380 on the host's enp3s0. > > To save myself from configuring all VLANs on the KVM host, I'd like to > hand the entire ethernet link to the VM and to have the VLAN interfaces > there. Using classical Linux bridges (brctl), things work fine. > > They don't when I try macvlan: > > On the host: > 4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff promiscuity 1 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 5: unt382@enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff promiscuity 0 > vlan protocol 802.1Q id 382 <REORDER_HDR> addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 15: macvtap3@enp3s0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 500 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 > macvtap mode bridge addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > > 4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff > inet6 fe80::20d:b9ff:fe34:2afe/64 scope link > valid_lft forever preferred_lft forever > 5: unt382@enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff > inet6 fe80::20d:b9ff:fe34:2afe/64 scope link > valid_lft forever preferred_lft forever > 15: macvtap3@enp3s0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 500 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff > inet6 fe80::5054:ff:febf:bbab/64 scope link > valid_lft forever preferred_lft forever > > > In the XML: > <interface type='direct'> > <mac address='52:54:00:bf:bb:ab'/> > <source dev='enp3s0' mode='bridge'/> > <target dev='macvtap3'/> > <model type='virtio'/> > <alias name='net0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> > </interface> > > And in the VM: > root@grml ~ # ip -d link show > 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 3: vlan0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 > vlan protocol 802.1Q id 382 <REORDER_HDR> addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > root@grml ~ # ip a > 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > inet 127.0.0.1/8 scope host lo > valid_lft forever preferred_lft forever > inet6 ::1/128 scope host > valid_lft forever preferred_lft forever > 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff > inet6 fe80::5054:ff:febf:bbab/64 scope link > valid_lft forever preferred_lft forever > 3: vlan0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff > inet 192.168.252.220/24 brd 192.168.252.255 scope global vlan0 > valid_lft forever preferred_lft forever > inet6 fe80::5054:ff:febf:bbab/64 scope link > valid_lft forever preferred_lft forever > root@grml ~ # > > I then ping from the VM to 192.168.252.241, which is a differnt host on > the network, neither the VM host the VM is running on nor another VM on > the same host. That should rule out the connectivity issues that a > macvtap interface has, right? On the VM, I see ARP requests going out, > but no answers come in. > > On the pinged host, I see: > 22:50:23.881163 52:54:00:bf:bb:ab > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.252.241 tell 192.168.252.220, length 46 > 22:50:23.881242 52:54:00:95:df:a6 > 52:54:00:bf:bb:ab, ethertype ARP (0x0806), length 42: Reply 192.168.252.241 is-at 52:54:00:95:df:a6, length 28 > > So, the packets going out from my VM are correctly delivered to the > target, the target replies, but the replies never make it back to the > VM. > > Do I see correctly that tcpdump on the VM host won't give accurate > readings since macvtap will divert the frame before tcpdump will see it? > > On the other hand, a VM directly configured to the host's unt382 > interface works fine: > <interface type='direct'> > <mac address='52:54:00:cb:ed:34'/> > <source dev='unt382' mode='bridge'/> > <model type='virtio'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> > </interface> > I would however like to avoid having 25 interface stanzas in my XML. > > I would appeciate any ideas to solve this issue. I know this is most > probably not a libvirt issue, but this list is about the only place that > comes to my mind where people knowledgeable about those complex network > stuff might hang around. If there is a better place to ask, I am open > for suggestion. Please pardon my intrusion. > > Greetings > Marc > > -- > ----------------------------------------------------------------------------- > Marc Haber | "I don't trust Computers. They | Mailadresse im Header > Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402 > Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421-- ----------------------------------------------------------------------------- Marc Haber | "I don't trust Computers. They | Mailadresse im Header Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402 Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421
On 12/16/18 4:59 PM, Marc Haber wrote:> Hi, > > I would like to run a network firewall as a VM on a KVM host. There are > ~ 25 VLANs delivered to the KVM host on three dedicated links, no LACP > or other things. I have the VLANs 100-180 on the host's enp1s0, the VLANs > 200-280 on the host's enp2s0 and the VLANs 300-380 on the host's enp3s0. > > To save myself from configuring all VLANs on the KVM host, I'd like to > hand the entire ethernet link to the VM and to have the VLAN interfaces > there. Using classical Linux bridges (brctl), things work fine.When I asked the person I go to with questions about macvtap (because he knows the internals), his response was "if a Linux host bridge works, then he should use that". In other words, he was skeptical that what you want to do could be made to work with macvtap. Is there a specific reason you need to use macvtap than a Linux host bridge?> > They don't when I try macvlan: > > On the host: > 4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff promiscuity 1 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 5: unt382 at enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff promiscuity 0 > vlan protocol 802.1Q id 382 <REORDER_HDR> addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 15: macvtap3 at enp3s0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 500 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 > macvtap mode bridge addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > > 4: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff > inet6 fe80::20d:b9ff:fe34:2afe/64 scope link > valid_lft forever preferred_lft forever > 5: unt382 at enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 > link/ether 00:0d:b9:34:2a:fe brd ff:ff:ff:ff:ff:ff > inet6 fe80::20d:b9ff:fe34:2afe/64 scope link > valid_lft forever preferred_lft forever > 15: macvtap3 at enp3s0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 500 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff > inet6 fe80::5054:ff:febf:bbab/64 scope link > valid_lft forever preferred_lft forever > > > In the XML: > <interface type='direct'> > <mac address='52:54:00:bf:bb:ab'/> > <source dev='enp3s0' mode='bridge'/> > <target dev='macvtap3'/> > <model type='virtio'/> > <alias name='net0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> > </interface> > > And in the VM: > root at grml ~ # ip -d link show > 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > 3: vlan0 at eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff promiscuity 0 > vlan protocol 802.1Q id 382 <REORDER_HDR> addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 > root at grml ~ # ip a > 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > inet 127.0.0.1/8 scope host lo > valid_lft forever preferred_lft forever > inet6 ::1/128 scope host > valid_lft forever preferred_lft forever > 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff > inet6 fe80::5054:ff:febf:bbab/64 scope link > valid_lft forever preferred_lft forever > 3: vlan0 at eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 > link/ether 52:54:00:bf:bb:ab brd ff:ff:ff:ff:ff:ff > inet 192.168.252.220/24 brd 192.168.252.255 scope global vlan0 > valid_lft forever preferred_lft forever > inet6 fe80::5054:ff:febf:bbab/64 scope link > valid_lft forever preferred_lft forever > root at grml ~ # > > I then ping from the VM to 192.168.252.241, which is a differnt host on > the network, neither the VM host the VM is running on nor another VM on > the same host. That should rule out the connectivity issues that a > macvtap interface has, right? On the VM, I see ARP requests going out, > but no answers come in. > > On the pinged host, I see: > 22:50:23.881163 52:54:00:bf:bb:ab > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.252.241 tell 192.168.252.220, length 46 > 22:50:23.881242 52:54:00:95:df:a6 > 52:54:00:bf:bb:ab, ethertype ARP (0x0806), length 42: Reply 192.168.252.241 is-at 52:54:00:95:df:a6, length 28 > > So, the packets going out from my VM are correctly delivered to the > target, the target replies, but the replies never make it back to the > VM. > > Do I see correctly that tcpdump on the VM host won't give accurate > readings since macvtap will divert the frame before tcpdump will see it? > > On the other hand, a VM directly configured to the host's unt382 > interface works fine: > <interface type='direct'> > <mac address='52:54:00:cb:ed:34'/> > <source dev='unt382' mode='bridge'/> > <model type='virtio'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> > </interface> > I would however like to avoid having 25 interface stanzas in my XML. > > I would appeciate any ideas to solve this issue. I know this is most > probably not a libvirt issue, but this list is about the only place that > comes to my mind where people knowledgeable about those complex network > stuff might hang around. If there is a better place to ask, I am open > for suggestion. Please pardon my intrusion. > > Greetings > Marc >
Hi Laine, thanks for your answer, I really appreciate that. On Wed, Jan 02, 2019 at 11:34:30AM -0500, Laine Stump wrote:> On 12/16/18 4:59 PM, Marc Haber wrote: > > I would like to run a network firewall as a VM on a KVM host. There are > > ~ 25 VLANs delivered to the KVM host on three dedicated links, no LACP > > or other things. I have the VLANs 100-180 on the host's enp1s0, the VLANs > > 200-280 on the host's enp2s0 and the VLANs 300-380 on the host's enp3s0. > > > > To save myself from configuring all VLANs on the KVM host, I'd like to > > hand the entire ethernet link to the VM and to have the VLAN interfaces > > there. Using classical Linux bridges (brctl), things work fine. > > When I asked the person I go to with questions about macvtap (because he > knows the internals), his response was "if a Linux host bridge works, then > he should use that". In other words, he was skeptical that what you want to > do could be made to work with macvtap.I see. A Linux host bridge is what I build with brctl?> Is there a specific reason you need to use macvtap than a Linux host bridge?I somehow got the impression that using macvtap is the more "modern" and also more performant approach to bring network to VMs. Since the VM in question is a Firewall, I'd love to have the performance impact caused by virtualization minimized[1]. If this is a misconception, it might have been partially caused by some colleagues at my last customer's site who very vocal about deprecating the classical brctl bridges in favor of macvtap/macvlan, and the fact that virt-manager uses macvtap by default and needs to be massaged into allowing a classic brctl bridge. Greetings Marc [1] The transfer rate of a tunneled IPv6 link with a dedicated VM handling the tunnel and a dedicated VM handling firewalling with brctl bridges (ingress packet - hypervisor - firewall VM - hypervisor - tunnel VM - hypervisor - firewall VM - hypervisor - egress packet) maxes out at about 15 Mbit on the APU device being used, with negligible load on the two VMs and the hypervisor kernel spending a non-negligible amount of its time inside the kernel wich I interpret as the context changes killing the machine -- ----------------------------------------------------------------------------- Marc Haber | "I don't trust Computers. They | Mailadresse im Header Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402 Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421