Cant get Network Bridge to work propperly

Issues related to configuring your network
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AimLikeAProtato
Posts: 2
Joined: 2020/07/17 12:11:37

Cant get Network Bridge to work propperly

Post by AimLikeAProtato » 2020/07/17 12:20:36

Hello,
I have a problem setting up our Centos 8.2.2004 as Hypervisor. I want to have a network Bridge with an IP Adress to access the server. The Guest systems would connect to this bridge to get their own ip adress.
Our Network is:

192.168.0.0/24
Gateway: 192.168.0.1
DNS: 192.168.0.1,192.168.0.4
Hypervisor: 192.168.0.202 (temporary)

i used nmcli to add the bridge br1 to the interface enp1s0f3

My Problem is that i am able to ping the gateway from the hypervisor. I can not ping the hypervisor from the gateway
I can not ping out of out network like 8.8.8.8

Does anyone know were there might be a mistake or what i am missing???

here is some usefull information like connections and config files:
[root@localhost ~]# nmcli connection show
NAME UUID TYPE DEVICE
enp1s0f2 96e96965-4caf-4505-992e-f7f3d7bc879a ethernet enp1s0f2
br1 50661144-28c6-47a8-a8cb-63e5874094e5 bridge br1
enp1s0f3 1c257f17-96ab-4f20-92ca-808f1bc62b67 ethernet enp1s0f3
enp1s0f0 7e9d5322-5f5f-4e33-a2b4-3cab4a93a487 ethernet --
enp1s0f1 d5e0ce14-a2ae-43e3-8b46-5dab78c1a27b ethernet --
enp7s0f3u2u3c2 4c4d06fc-c0b3-4993-94c6-40321d0b1900 ethernet --

[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-br1
STP=no
BRIDGING_OPTS=priority=32768
TYPE=Bridge
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=br1
UUID=50661144-28c6-47a8-a8cb-63e5874094e5
DEVICE=br1
ONBOOT=yes
IPADDR=192.168.0.202
PREFIX=24
GATEWAY=192.168.0.1
DNS1=192.168.0.4
DNS2=192.168.0.1
DNS3=1.1.1.1

[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-enp1s0f3
TYPE=Ethernet
NAME=enp1s0f3
UUID=1c257f17-96ab-4f20-92ca-808f1bc62b67
DEVICE=enp1s0f3
ONBOOT=yes
BRIDGE=br1

User avatar
jlehtone
Posts: 2921
Joined: 2007/12/11 08:17:33
Location: Finland

Re: Cant get Network Bridge to work propperly

Post by jlehtone » 2020/07/17 13:49:53

Code: Select all

enp1s0f2 96e96965-4caf-4505-992e-f7f3d7bc879a ethernet enp1s0f2
br1 50661144-28c6-47a8-a8cb-63e5874094e5 bridge br1
enp1s0f3 1c257f17-96ab-4f20-92ca-808f1bc62b67 ethernet enp1s0f3
I see that br1 is not your only connection. The config of enp1s0f2 can probably explain some of your issues.

Elementary check, what you get with:

Code: Select all

ip ro

AimLikeAProtato
Posts: 2
Joined: 2020/07/17 12:11:37

Re: Cant get Network Bridge to work propperly

Post by AimLikeAProtato » 2020/07/17 14:01:52

in the meantime i tried to redo the whole configuration. Nothing changed except i deleted the old bridge and the new name is br2. still the same issues.
I have also seen the behaviour that sometimes if i ping the system i get 1 reply and then nothing.

ip ro command is now:

default via 192.168.0.1 dev br2 proto static metric 425
192.168.0.0/24 dev br2 proto kernel scope link src 192.168.0.202 metric 425
192.168.122.0/24 dev vibro proto kernel scope link src 192.168.122.1 linkdown

leifh
Posts: 17
Joined: 2009/02/24 21:19:12
Location: Norway

Re: Cant get Network Bridge to work propperly

Post by leifh » 2020/07/30 11:25:56

Hi, have an (almost) indentical setup. Using vlans on my bridges, but config should be similar.
I am using nmcli commands to setup my network configuration (tested on centos 8.1 and 8.2)

the example underneath have not been tested, but should work.

ipv4 and ipv6 disabled on my interface when i start. no other default routes active on any other interfaces.

# cat /etc/sysconfig/network-scripts/ifcfg-ens1f0
TYPE=Ethernet
DEVICE=ens1f0
ONBOOT=no
IPV6INIT=no
PROXY_METHOD=none
BROWSER_ONLY=no
NAME="System ens1f0"

First i create my bridge:
nmcli con add type bridge ifname br1 con-name br1 ipv4.method manual ipv4.addresses "192.168.0.202" ipv4.dns "192.168.0.4,192.168.0.1" ipv4.gateway "192.168.0.1" connection.autoconnect yes ipv6.method disabled

]# cat /etc/sysconfig/network-scripts/ifcfg-br1
STP=yes
BRIDGING_OPTS=priority=32768
TYPE=Bridge
PROXY_METHOD=none
BROWSER_ONLY=no
IPV6_DISABLED=yes
IPV6INIT=no
NAME=br1
DEVICE=br1
ONBOOT="yes"
BOOTPROTO="static"
IPADDR="192.168.0.202"
NETMASK="255.255.255.0"
GATEWAY="192.168.0.1"
IPV6INIT="no"
DNS1="192.168.0.4"
DNS2="192.168.0.1"
DNS3=""


Then ! tell ens1f0 br1 is master (added autostart connection, not sure it is needed)
#nmcli connection modify ens1f0 master br1 slave-type bridge connection.autoconnect yes

#nmcli con up br1

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