IP alias can't reach default gateway

[Isidro Jose Hortelano]

Hello,

I'm having an odd issue, I have configured a  server with a primary address and secondary IP through IP alias. I added the secondary as static IP in /etc/sysconfig/network/ifcfg-eth0.

cat /etc/sysconfig/network/ifcfg-eth0 
BOOTPROTO='dhcp'                                                                                                        
STARTMODE='onboot'                                                                                                  
IPADDR_1='10.10.0.100/32'

I'm facing a connection issue when the secondary IP comes first, the outgoing traffic doesn't work, checking with tcpdump I saw that I only have connection when the pkg comes from the primary IP as source.

Can I configure any firewall  rule, routing, etc to avoid this? or  GCP only accepts pkg when the ip src is the primary IP.

Thanks,