networks: add multiple IP addresses from 2 different subnets to my interface


I am trying to configure squid with my Ubuntu 16.04 server. I configured everything with my first subnet (which shares the gateway with my server's IP address). My provider has added 2 different networks to my server, and I can't add the second half to my interface. For clarity purposes, I will use fake IP to explain my problem:

My server IP: 178.212.145.130

Running sudo ip addr gives me:

1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp1s0f0:  mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether ac:1f:6b:9b:31:f2 brd ff:ff:ff:ff:ff:ff
3: enp1s0f1:  mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether ac:1f:6b:9b:31:f3 brd ff:ff:ff:ff:ff:ff
    inet 178.212.145.130/25 brd 178.212.145.255 scope global enp1s0f1
       valid_lft forever preferred_lft forever
    inet6 fe80::ae1f:645f:f22b:31f3/64 scope link
       valid_lft forever preferred_lft forever

So as I understand I have 2 network adapters to work: enp1s0f0 Y enp1s0f1

First network I received:

178.212.145.131
178.212.145.132
178.212.145.133
...
...
...
178.212.145.254

Gateway of my first network: 178.212.145.129

Second network I received:

81.12.206.130
81.12.206.131
81.12.206.132
81.12.206.133
...
...
...
81.12.206.254

Second network gateway: 81.12.206.129

My default Network Interfaces setting (with only my server IP added):

auto lo
iface lo inet loopback
auto enp1s0f1
iface enp1s0f1 inet static
    address 178.212.145.130
    netmask 255.255.255.128
    gateway 178.212.145.129

I have added the first half of my network using the following method:

auto lo
iface lo inet loopback
auto enp1s0f1
iface enp1s0f1 inet static
    address 178.212.145.130
    netmask 255.255.255.128
    gateway 178.212.145.129

auto enp1s0f1:1

iface enp1s0f1:2 inet static
address 178.212.145.131
netmask 255.255.255.128

auto enp1s0f1:2

iface enp1s0f1:2 inet static
address 178.212.145.132
netmask 255.255.255.128

..... (and so on)

auto enp1s0f1:124

iface enp1s0f1:124 inet static
address 178.212.145.254
netmask 255.255.255.128

Now when I try to do the same for the second part, that's where my problem occurs.
I tried to use the same adapter and add this to my network interface:

auto enp1s0f1:125
iface enp1s0f1:125 inet static
    address 81.12.206.130
    netmask 255.255.255.128
    gateway 81.12.206.129

and tried to use the other free adapter:

auto enp1s0f0
iface enp1s0f0 inet static
    address 81.12.206.130
    netmask 255.255.255.128
    gateway 81.12.206.129

After changing this in my interfaces file I do the old service networking restart however I receive

Job for networking.service failed because the control process exited with error code. See "systemctl status networking.service" and "journalctl -xe" for details.

The error occurs due to: Failed to bring up enp1s0f1:125. (method 1) or Failed to bring up enp1s0f0. (method 2)

What exactly am I doing wrong here?

Thanks in advance and I hope I have given enough information!