Interface grouping is available on FreeBSD and OpenBSD. This will allow
you to enumerate only SoftEther virtual interfaces or exclude SoftEther
virtual interfaces, and be helpful when making custom scripts to start
DHCP client when virtual interface become up (=VPN connection
established) for example.
Usage examples as follows.
List all interfaces' names available on the system:
```
$ ifconfig -l
vtnet0 lo0 vpn_client0 vpn_client1 vpn_client2
```
Display a list of SoftEther virtual interfaces:
```
$ ifconfig -g softether
vpn_client0
vpn_client1
vpn_client2
```
Display details about SoftEther virtual interfaces that are up:
```
$ ifconfig -a -u -g softether
vpn_client0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
description: SoftEther Virtual Network Adapter
options=80000<LINKSTATE>
ether 5e:71:fa:f8:91:4a
hwaddr 58:9c:fc:10:34:2a
groups: tap softether
media: Ethernet autoselect
status: active
nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
Opened by PID 1445
```
Display details about interfaces except for SoftEther virtual interfaces:
```
$ ifconfig -a -G softether
vtnet0: flags=8863<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=80028<VLAN_MTU,JUMBO_MTU,LINKSTATE>
ether 58:9c:fc:00:f0:23
inet6 fe80::5a9c:fcff:fe00:f023%vtnet0 prefixlen 64 scopeid 0x1
inet 192.168.96.7 netmask 0xffffff00 broadcast 192.168.96.255
media: Ethernet autoselect (10Gbase-T <full-duplex>)
status: active
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2
inet 127.0.0.1 netmask 0xff000000
groups: lo
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
```
