multiple ipv4 addresses with internet connection on single physical device

Question

my isp gives me up to two ipv4 addresses. i have a raspberry pi with archlinux connected to the modem. first interface is eth0 and the ip address is obtained via dhcp.

i created a virtual device with

ip link add link eth0 address 00:11:11:11:11:11 eth0.1 type macvlan

and gave that device an ip with

dhcpcd eth0.1

my routing table now looks like (i changed the public adresses to 10.0.x.x):

[root@core ~]# ip route
default via 10.0.26.1 dev eth0  metric 204 
default via 10.0.24.1 dev eth0.1  metric 206 
10.0.24.0/23 dev eth0.1  proto kernel  scope link  src 10.0.24.195  metric 206 
10.0.26.0/24 dev eth0  proto kernel  scope link  src 10.0.26.219  metric 204 
192.168.178.0/24 dev eth1  proto kernel  scope link  src 192.168.178.1

with firewall and everything disabled i tried

ping -I eth0.1 www.google.de

but that did not work.

i changed the metric from the 2nd route from 206 to 100 and then it worked. but now pings from eth0 are broken.

as far as my network understanding goes, i expect that pinging from both devices should be working.

my next action was to dump traffic (i changed my public ip to 10.0.x.x)

[root@core ~]# ping -I eth0.1 www.google.de (no output was shown here)
[root@core ~]# tcpdump -i eth0.1 icmp
11:32:18.344731 IP  10.0.24.195 > ham02s11-in-f23.1e100.net: ICMP echo request, id 1841, seq 1, length 64
11:32:18.368186 IP ham02s11-in-f23.1e100.net > 10.0.24.195: ICMP echo reply, id 1841, seq 1, length 64

i also looked at the dump in wireshark, for me it looked perfectly cool. arp and ip addresses of eth0.1 were used. (00:11:11:11:11:11 and 10.0.24.195)

here is the output of my interface informations

[root@core ~]# ip addr
4: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group   default qlen 1000
link/ether b8:27:eb:fe:e6:87 brd ff:ff:ff:ff:ff:ff
inet 10.0.26.219/24 brd 10.0.26.255 scope global eth0
   valid_lft forever preferred_lft forever
6: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default 
link/ether 00:11:11:11:11:11 brd ff:ff:ff:ff:ff:ff
inet 10.0.24.195/23 brd 10.0.25.255 scope global eth0.1
   valid_lft forever preferred_lft forever

i noticed some things that seem weird to me, but iam not sure.

• state of eth0.1 UNKNOWN
• netmask of eth0.1 is /23 , not /24
• brd of eth0.1 is 10.0.25.255, compared to eth0 i would expect 10.0.24.255

i hope anyone can give me some advice.