[CentOS] CentOS 7 host with guests as bridge cannot access host

Wed Apr 1 18:11:47 UTC 2020
Alexander Dalloz <ad+lists at uni-x.org>

Am 01.04.2020 um 14:53 schrieb Jerry Geis:
> I have CentOS 7 host. Two guests on bridge network setup by GUI and
> virt-manager.
> 1 CentOS 8 guest
> 1 Win 10 guest
> Both cannot access the host. They can other machines on the network. Guests
> can access the internet just not the host.
> 
> I used virt-manager GUi to set up everything. Selected the eth0:macvtap and
> Bridge.
> I "desire" bridge network.
> 
> If I select something else I get access to host - but of course machine is
> not on the main network.
> 
> Thoughts ?
> 
> Jerry

WORKSFORME

What have you checked so far?

On the host:

# brctl show virbr1
bridge name     bridge id               STP enabled     interfaces
virbr1          8000.525400698fd5       yes             virbr1-nic
                                                         vnet0
                                                         vnet1
                                                         vnet2
                                                         vnet3
                                                         vnet4
                                                         vnet5


# ip a s virbr1
3: virbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue 
state UP group default qlen 1000
     link/ether 52:54:0069:8f:d5 brd ff:ff:ff:ff:ff:ff
     inet 192.168.10.1/24 brd 192.168.10.255 scope global virbr1
        valid_lft forever preferred_lft forever

# cat /proc/sys/net/ipv4/ip_forward
1

# iptables -L FORWARD -v -n | egrep '(policy|virbr1)'
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
20337   14M ACCEPT     all  --  eno1   virbr1  0.0.0.0/0 
192.168.10.0/24      ctstate RELATED,ESTABLISHED
29512 3243K ACCEPT     all  --  virbr1 eno1    192.168.10.0/24 
0.0.0.0/0
     0     0 ACCEPT     all  --  virbr1 virbr1  0.0.0.0/0 
0.0.0.0/0
     0     0 REJECT     all  --  *      virbr1  0.0.0.0/0 
0.0.0.0/0            reject-with icmp-port-unreachable
     0     0 REJECT     all  --  virbr1 *       0.0.0.0/0 
0.0.0.0/0            reject-with icmp-port-unreachable

Alexander