Cannot establish an IPv4 connection from my bridge to an external node on the same network (IPv6 works tho)

network-dummy

6/6/24, 7:58 PM

I am currently trying to build a little lab for testing purposes:

I have a Linux Host-System (currently Arch-Based)deploying 2 vms, abridge with an assigned NIC and a CISCO Router that is directly linked to the NIC that is enslaved to the bridge.

The VMs and the Host-System can ping each other via IPv6 and via IPv4, the router is only pingable via IPv6, and I am not sure why.

The Router has the addresses: 203.0.113.3/24 and 2001:db8:dead:beef::3/64 The VM(s) has the addresses: 203.0.113.4/24 and 2001:db8:dead:beef::4/64 The Bridge has the addresses 203.0.113.1/24 and 2001:db8:dead:beef::1/64

The configuration is as follows:

br: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether aa:64:c7:9e:01:0a brd ff:ff:ff:ff:ff:ff
    inet 203.0.113.1/24 brd 203.0.113.255 scope global noprefixroute br4-a
       valid_lft forever preferred_lft forever
    inet6 2001:db8:dead:beef::1/64 scope global noprefixroute 
       valid_lft forever preferred_lft forever

eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br state UP group default qlen 1000
    link/ether 00:23:57:3c:98:79 brd ff:ff:ff:ff:ff:ff


Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
203.0.113.0     0.0.0.0         255.255.255.0   U     426    0        0 br

The firewall is currently disabled as this is a local lab.

I am probably missing something obvious, but I am not sure where to look.

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EN: Cannot establish an IPv4 connection from my bridge to an external node on the same network (IPv6 works tho)

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