I have modified my VM network to have multiple tagged networks. It used to be an untagged network and it worked fine, but I needed to add more networks on the host. The switch it is connected to has the port configured as a trunk port with these VLANs. When a VM sends traffic out (to get a DHCP address for instance), it reaches the server but does not get the DHCP offer that the server sends. I did a tcpdump on the node that hosts the VM and the packets going out do not have a VLAN tag. I assume the VM host interface would should not have the tag present, but that the  p2p1.91 interface should put the VLAN tag on.

The relevant interface configuration on the node that the VM host is on looks like:

27: sohonet_DMZ: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
    link/ether a0:36:9f:2a:63:20 brd ff:ff:ff:ff:ff:ff
29: p2p1.91@p2p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master vmnet state UP
    link/ether a0:36:9f:2a:63:20 brd ff:ff:ff:ff:ff:ff
30: vmnet: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
    link/ether a0:36:9f:2a:63:20 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::a236:9fff:fe2a:6320/64 scope link
       valid_lft forever preferred_lft forever
31: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmnet state UNKNOWN qlen 500
    link/ether fe:1a:4a:16:01:58 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc1a:4aff:fe16:158/64 scope link
       valid_lft forever preferred_lft forever
32: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vmnet state UNKNOWN qlen 500
    link/ether fe:1a:4a:16:01:5c brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc1a:4aff:fe16:15c/64 scope link
       valid_lft forever preferred_lft forever