CRS305-1G-4S+IN vs gigabit switch

RouterOS Beginner Basics
1

I have a problem when I install a new OS on my server, it defaults to dhcp, and all is ok. But when I set it to a static ip, nothing works for hours then magically, it starts to works.
So I created a simple static configuration, and now I think I don’t understand the CRS305.

Server 1 fiber -------------------------------------------> CRS305 ----> fiber Server 2
99.153.71.9 / 255.255.255.248 / 99.153.71.14 99.153.71.10 / 255.255.255.248 / 99.153.71.14

Server 1 Ethernet --------------------------------------> GigSwitch ----> Ethernet Server 2
99.153.72.9 / 255.255.255.248 / 99.153.72.14 99.153.72.10 / 255.255.255.248 / 99.153.72.14

ping 99.153.71.10 fails ping 99.153.71.9 fail
ping 99.153.72.10 works ping 99.153.72.9 works

No gateway present, just the CRS305 and GigSwitch.
My server are ubuntu 18.4
The CRS305 is default configuration.

I assumed that the sequence would be ARP, get a response, send a packet.

I tried connecting winbox box but have no idea where to look or what to do.

Any suggestions would be appreciated.

2

if you are making CRS305 as a switch remove the IP address that you assign on it and create a bridge and add two ethernet ports in the bridge and assign IP on your server and the fiber modem as you may call it and it should work

e.g

/interface/bridge/add name=BRIDGE
/interface/bridge/port add interface=sfp-sfpplus1 bridge=BRIDGE
/interface/bridge/port add interface=sfp-sfpplus2 bridge=BRIDGE

then plug your server on sfp-sfpplus1 and assign your desired IP and in the 2nd port plug your modem and assign your desired ip and it should work