How to organize a network of middle office?

Question

network hardware

Good day!
There is a task to organize a network of small office on ~50 PCs.
Given:
all lines go to the server room, but most of the cables in the server room end in switches in the cabinets to which the equipment is connected. Telephony goes separately.
There is 1 L3 switch (HPE 1920 JG927a)), an L2 switch (DGS-1210-52), several DGS-1024D gigabit unmanaged switches, a load balancer, a small server farm (7 pieces).
Now among the servers there is a "gateway server" on FreeBSD, which acts as a DHCP server and proxy server on Squid)
You need:
organize switching and routing (if possible, by available means, but not fundamentally), delimit some segments with VLANs based on MAC addresses. With all this, all traffic must go through a proxy in order to be able to regulate access.
I have practically no experience in organizing such networks, so I ask for help on some questions:
1) Would it be appropriate to use an L3 switch as a router to which L2 lumps will be connected?
2) How to correctly switch the proxy server? Balancer → Router (or "gateway server?) → Proxy → L2 switches?
Maybe my vision of this issue is generally ineffective, so I ask for help with advice from more experienced people. Thank you in advance for your answers.

Answer 1

hubs in offices

Yo, really hubs ? Not with switches? Then the point is zero - throw out all the hubs and replace them with switches. If the hubs are multiport - 24 or more - install managed switches.
1. An L3 switch is an L3 switch, NOT a router. Do not pull the owl on the globe :)
2. Proxy - as a rule, a virtual machine standing in the server room, directly in front of the gateway

Answer 2

php.net/manual/en/function.explode.php