I'm upgrading my desktop from CentOS-6 to Debian -- CentOS-8 has Gnome 3 that I can't abide, Debian has Mate.
Most of it works nicely; one problem is starting a network bridge takes down the ethernet connection. Can anyone please offer any clues: /etc/network/interfaces.d/br0 contains: iface br0 inet static bridge_ports enp3s0 address 10.239.239.254 broadcast 10.239.239.255 netmask 255.255.255.0 # Without this: when a VM starts the rest of the machine loses Internet connectivity - dunno why bridge_stp off bridge_maxwait 0 bridge_fd 0 /etc/network/interfaces.d/enp3s0 contains: auto enp3s0 iface enp3s0 inet static address 192.188.145.2 broadcast 192.188.145.255 netmask 255.255.255.0 gateway 192.188.145.1 (It is a wired [utp] ethernet) (Loopback is also defined somewhere) Note that br0 is NOT brought up automatically (although I will want that eventually.) I bring it all up and then: ifup br0 And some time later enp3s0 will stop. 'Some time' varies, I have seen 5 minutes and 45 minutes. Without br0 it has been stable - ie about a day. It failed just now (after I brought up br0), there was little network activity: a bit of web browsing; SMTP in/out; idle openvpn; a ping to news.bbc.co.uk Relevant lines from /var/log/messages: When I typed: ifup br0 Nov 14 12:30:51 mint kernel: [96153.146266] br0: port 1(enp3s0) entered blocking state Nov 14 12:30:51 mint kernel: [96153.146269] br0: port 1(enp3s0) entered disabled state Nov 14 12:30:51 mint kernel: [96153.146396] device enp3s0 entered promiscuous mode Nov 14 12:30:51 mint kernel: [96153.190042] br0: port 1(enp3s0) entered blocking state Nov 14 12:30:51 mint kernel: [96153.190046] br0: port 1(enp3s0) entered forwarding state Nov 14 12:30:51 mint kernel: [96153.190140] IPv6: ADDRCONF(NETDEV_UP): br0: link is not ready Nov 14 12:30:52 mint kernel: [96154.164444] IPv6: ADDRCONF(NETDEV_CHANGE): br0: link becomes ready A few minutes after it failed when I typed: ifdown br0 ifdown enp3s0 ifup enp3s0 Nov 14 13:19:36 mint kernel: [99078.474136] br0: port 1(enp3s0) entered disabled state Nov 14 13:19:36 mint kernel: [99078.554460] device enp3s0 left promiscuous mode Nov 14 13:19:36 mint kernel: [99078.554492] br0: port 1(enp3s0) entered disabled state Nov 14 13:19:59 mint kernel: [99101.806231] RTL8211E Gigabit Ethernet r8169-300:00: attached PHY driver [RTL8211E Gigabit Ethernet] (mii_bus:phy_addr=r8169-300:00, irq=IGNORE) Nov 14 13:20:02 mint kernel: [99104.114206] r8169 0000:03:00.0 enp3s0: Link is Up - 1Gbps/Full - flow control off /var/log/syslog tells me that it failed a few minutes before I noticed: Nov 14 13:14:24 mint openvpn[3435]: TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity) Nov 14 13:14:24 mint openvpn[3435]: TLS Error: TLS handshake failed Why to I want br0 ? ******************* The reason that I want a bridge is so that virtual machines (under kvm) can connect to the host machine and to the Internet. This problem happens even if VMs are not running. My machine has: enp3s0 192.168.145.2 - connected to broadband router I want: br0 10.239.239.254 Virtual machines with addresses like 10.239.239.12 that they can see the outside world. -- Alain Williams Linux/GNU Consultant - Mail systems, Web sites, Networking, Programmer, IT Lecturer. +44 (0) 787 668 0256 https://www.phcomp.co.uk/ Parliament Hill Computers Ltd. Registration Information: https://www.phcomp.co.uk/Contact.html #include <std_disclaimer.h>