networking - Datacenter ISP wants to assign an IP range to an existing ip address that we already use

itemprop="text">

I have a question about the setup of
our data center regarding a new IP
range.

The situation is as
follows.

we own/use a range x.x.x.x/28 we got it
already from our data center.
we have 16 addresses we already use for our
servers (13 actually without network, broadcast and default
gateway)

Now we want to order another range
y.y.y.y/27 that has 32-3 usable addresses I
presume.

Because they cannot assign this range
to the same network port where x.x.x.x/28 is assigned to, they ask me for an ip address
within the x.x.x.x/28 range, let's say a.a.a.a. to route the new range (y.y.y.y/27)
to.

The other solution is to hire a new network
port to which the y.y.y.y/27 range can be routed through
normally.

My account manager is a bit
vague and we can't afford to switch data center right
now.

So my question
is;

how do I configure this?
does
a.a.a.a become the default gateway somehow? I can't get a clear apprehension of how this
technically should work. Is there a special name for this type of routing? Google
doesn't give me any clear answers, because I don't know exactly what I'm looking
for.

I hope someone can shine a light for me on
this
one.

Thx

Bram

Answer

Your server which has a.a.a.a address assigned will
receive traffic addressed to network y.y.y.y/27. You can assign
addresses from the y.y.y.y/27 range as an IP aliases on the
same network interface as a.a.a.a by using ip addr
add y.y.y.y dev eth0 or you can route them to other servers by using
ip route add y.y.y.y via a.a.a.x
(a.a.a.x is a different server from range
x.x.x.x/28)