Two different Network interfaces simultaniously CentOS

im going nuts since i'm tryin to solve this for nearly a week now.

Scenario: One Server with two different network devices. Each device is plugged into a different company subnet. eth0 is plugged in x.y.5.184/29, while eth1 is plugged into x.y.88.224/27. I want the server to listen on both devices. Server-IP in .5.184/29 shall be x.y.5.186, Server-IP in .88.224/27 shall be x.y.88.253. I'd like to run two different VMs with Apache, so the Server shall – with natpf to the respective VM – listen on x.y.5.186:p1 for VM1 and on x.y.88.253:p2 for VM2

x and y have to be hidden due to privacy issues, but are given values.

So here is the problem: If i tu up eth1, the server is not responding on eth0 and i don't really know why. Here is some output with both devices up:

[user@server ~]$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    inet x.y.5.186  netmask 255.255.255.248  broadcast x.y.5.191
    ether <MAC>  txqueuelen 1000  (Etheet)
    RX packets 77141  bytes 50779367 (48.4 MiB)
    RX errors 27  dropped 0  overruns 26  frame 1
    TX packets 83841  bytes 63781133 (60.8 MiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    inet x.y.88.253  netmask 255.255.255.224  broadcast x.y.88.255
    ether <MAC>  txqueuelen 1000  (Etheet)
    RX packets 77911  bytes 6285521 (5.9 MiB)
    RX errors 0  dropped 836  overruns 0  frame 0
    TX packets 6502  bytes 1057860 (1.0 MiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
    inet 127.0.0.1  netmask 255.0.0.0
    inet6 ::1  prefixlen 128  scopeid 0x10<host>
    loop  txqueuelen 0  (Local Loopback)
    RX packets 740  bytes 606784 (592.5 KiB)
    RX errors 0  dropped 0  overruns 0  frame 0
    TX packets 740  bytes 606784 (592.5 KiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
    inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
    ether 52:54:00:67:e6:77  txqueuelen 0  (Etheet)
    RX packets 0  bytes 0 (0.0 B)
    RX errors 0  dropped 0  overruns 0  frame 0
    TX packets 0  bytes 0 (0.0 B)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 [user@server ~]$ route -n
Keel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         x.y.5.185    0.0.0.0         UG    0      0        0 eth0
0.0.0.0         x.y.88.225   0.0.0.0         UG    10     0        0 eth1
x.y.5.184    0.0.0.0         255.255.255.248 U     0      0        0 eth0
x.y.88.224   0.0.0.0         255.255.255.224 U     10     0        0 eth1
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0

[user@server ~]$ cat /etc/sysconfig/network-scripts/ifcfg-eth0
# ifcfg-eth0
HWADDR=<MAC>
TYPE=Etheet
BOOTPROTO=none
#DNS1=x.y.company.dns
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV4_ROUTE_METRIC=0
IPV6INIT=no
IPV6_AUTOCONF=no
IPV6_DEFROUTE=no
IPV6_FAILURE_FATAL=no
NAME=SERVER
UUID=<uuid>
DEVICE=eth0
ONBOOT=yes
IPADDR=x.y.5.186
PREFIX=29
GATEWAY=x.y.5.185


[user@server ~]$ cat /etc/sysconfig/network-scripts/ifcfg-eth1
# ifcfg-eth1
HWADDR=<MAC2>
TYPE=Etheet
BOOTPROTO=none
#DNS1=x.y.company.dns
DEFROUTE=no
IPV4_FAILURE_FATAL=yes
IPV4_ROUTE_METRIC=10
IPV6INIT=no
IPV6_AUTOCONF=no
IPV6_DEFROUTE=no
IPV6_FAILURE_FATAL=no
NAME=CLIENT
UUID=<uuid2>
DEVICE=eth1
ONBOOT=no
IPADDR=x.y.88.253
PREFIX=27
GATEWAY=x.y.88.225

So my thought is: might be a route. I deleted /etc/sysconfig/network-scripts/route-eth0 and route-eth1, so those are the defaults.

[user@server ~]$ ip route
default via x.y.5.185 dev eth0  proto static
default via x.y.88.225 dev eth1  proto static  metric 10
x.y.5.184/29 dev eth0  proto keel  scope link  src x.y.5.186
x.y.88.224/27 dev eth1  proto keel  scope link  src x.y.88.253  metric 1
192.168.122.0/24 dev virbr0  proto keel  scope link  src 192.168.122.1

i delete the default route for eth1

[root@server user]#  ip route del default via x.y.88.225 dev eth1  prot

and still nothing changes. Ping to eth0 ip fails. but if i delete the other route with

[root@server user]#  ip route del x.y.88.224/27 dev eth1  proto keel ric 10

eth0 works again, every connection to x.y.5.186 works again, but eth1 stops to work .... As far as i know the metric i used on eth1 should solve the issue, buuuut doesn't. Any routing expert with a thought on this?

Edit: fresh CentOS

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