Originally Posted by NotionCommotion
The Raspberry Pi is not the same as the router.
Why is it absolutely normal to have more than one IP address on an interface? Is it primarily to support virtual servers?
I ended up deleting the second IP, and think I have it resolved.
update-rc.d dhcpcd disable
service dhcpcd stop
ip addr del 192.168.1.173/24 dev eth0
The typical use case is web servers, indeed. Especially when serving https.
dhcpcd should use the configuration in the interfaces file. I do wonder whether your solution is sufficient.