Help: br0 brings down ethernet
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>
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