# /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug enp2s0
iface enp2s0 inet dhcp

# The wlan network interface
allow-hotplug wlp4s0
iface wlp4s0 inet manual

# Bridge interface
# IP static here, such that all VMs/WLAN clients can reach the host
auto br0
iface br0 inet static
    address 192.168.0.1/24
    bridge_ports none
    post-up /usr/sbin/hostapd \
        -P /var/run/hostapd.$IFACE.pid \
        -B /etc/hostapd/hostapd.conf
    pre-down cat /var/run/hostapd.$IFACE.pid | xargs kill

# Journalctl logs

Apr 18 00:34:24 homelab systemd[1]: Started Login Service.
Apr 18 00:34:24 homelab systemd-udevd[326]: Using default interface naming scheme 'v240'.
Apr 18 00:34:24 homelab kernel: bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
Apr 18 00:34:24 homelab systemd-udevd[326]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Apr 18 00:34:24 homelab systemd-udevd[326]: Could not generate persistent MAC address for br0: No such file or directory
Apr 18 00:34:24 homelab ifup[537]: Waiting for br0 to get ready (MAXWAIT is 32 seconds).
Apr 18 00:34:24 homelab dhclient[559]: Listening on LPF/enp2s0/d8:cb:8a:9c:c7:87
Apr 18 00:34:24 homelab sh[538]: Listening on LPF/enp2s0/d8:cb:8a:9c:c7:87
Apr 18 00:34:24 homelab sh[538]: Sending on   LPF/enp2s0/d8:cb:8a:9c:c7:87
Apr 18 00:34:24 homelab sh[538]: Sending on   Socket/fallback
Apr 18 00:34:24 homelab sh[538]: DHCPDISCOVER on enp2s0 to 255.255.255.255 port 67 interval 7
Apr 18 00:34:24 homelab dhclient[559]: Sending on   LPF/enp2s0/d8:cb:8a:9c:c7:87
Apr 18 00:34:24 homelab dhclient[559]: Sending on   Socket/fallback
Apr 18 00:34:24 homelab dhclient[559]: DHCPDISCOVER on enp2s0 to 255.255.255.255 port 67 interval 7
Apr 18 00:34:24 homelab ifup[537]: Configuration file: /etc/hostapd/hostapd.conf
Apr 18 00:34:24 homelab ifup[537]: Could not read interface wlp4s0 flags: No such device
Apr 18 00:34:24 homelab ifup[537]: nl80211: Driver does not support authentication/association or connect commands
Apr 18 00:34:24 homelab ifup[537]: nl80211: deinit ifname=wlp4s0 disabled_11b_rates=0
Apr 18 00:34:24 homelab ifup[537]: Could not read interface wlp4s0 flags: No such device
Apr 18 00:34:24 homelab ifup[537]: nl80211 driver initialization failed.
Apr 18 00:34:24 homelab ifup[537]: wlp4s0: interface state UNINITIALIZED->DISABLED
Apr 18 00:34:24 homelab ifup[537]: wlp4s0: AP-DISABLED
Apr 18 00:34:24 homelab ifup[537]: wlp4s0: CTRL-EVENT-TERMINATING
Apr 18 00:34:24 homelab ifup[537]: hostapd_free_hapd_data: Interface wlp4s0 wasn't started
Apr 18 00:34:24 homelab ifup[537]: ifup: failed to bring up br0
Apr 18 00:34:24 homelab systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Apr 18 00:34:24 homelab systemd[1]: networking.service: Failed with result 'exit-code'.
Apr 18 00:34:24 homelab systemd[1]: Failed to start Raise network interfaces.
Apr 18 00:34:24 homelab systemd[1]: Reached target Network.
Apr 18 00:34:24 homelab systemd[1]: Starting Permit User Sessions...
Apr 18 00:34:24 homelab systemd[1]: Starting Unbound DNS server...
Apr 18 00:34:24 homelab systemd[1]: Starting OpenBSD Secure Shell server...
Apr 18 00:34:24 homelab systemd[1]: Reached target Network is Online.
Apr 18 00:34:24 homelab systemd[1]: Started Permit User Sessions.
Apr 18 00:34:24 homelab systemd[1]: Started Getty on tty1.
Apr 18 00:34:24 homelab systemd[1]: Reached target Login Prompts.
Apr 18 00:34:24 homelab sshd[621]: Server listening on 0.0.0.0 port 22.
Apr 18 00:34:24 homelab sshd[621]: Server listening on :: port 22.
Apr 18 00:34:24 homelab systemd[1]: Started OpenBSD Secure Shell server.
Apr 18 00:34:24 homelab kernel: brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4366c-pcie for chip BCM4366/4
Apr 18 00:34:24 homelab kernel: brcmfmac 0000:04:00.0: firmware: failed to load brcm/brcmfmac4366c-pcie.clm_blob (-2)
Apr 18 00:34:24 homelab kernel: brcmfmac 0000:04:00.0: Direct firmware load for brcm/brcmfmac4366c-pcie.clm_blob failed with error -2
Apr 18 00:34:24 homelab kernel: brcmfmac: brcmf_c_process_clm_blob: no clm_blob available (err=-2), device may have limited channels available
Apr 18 00:34:24 homelab kernel: brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4366/4 wl0: Jan 15 2019 14:28:26 version 10.10.122.303 (r666429) FWID 01-9f64541d