Additional IP Addresses

[Guest]

My network addressing scheme can currently handle 254 hosts. The computers
are using static IP's rather than DHCP for security reasons. The scheme is
similar to the following: 10.10.0.1-10.10.0.255, Subnet Mask 255.255.255.0.


I need to add 50 hosts to my network within the next week and am out of
addresses. What would be the quickest, easiest, and most secure way to do
so?? Is DHCP the way to go?

 

[Phillip Windell]

I always recommend never going beyond 254 hosts per segment. So I would
recommend creating an additional subnet using for example
10.10.1.1-10.10.1.255. You need to buy a Router to route between the
subnets (a "real" router, not an Internet Sharing NAT Device).

Whether or not you use DHCP is irrelevant to the issue.

If you don't want to add a subnet you could adjust your current Mask to:
255.255.254.0 You would have to change it on every machine.

This would give you the

10.10.0.0 - 10.10.1.255 which give 510 usable host.

But I still don't recommend going over 254, so the two subnets (254 hosts in
each) are still what I recommend.

 

[BP]

If only one server and acting as system router it is possible
to add another nic for the additional subnet.

 

[Guest]

Phillip,

Thanks for the input. Generally speaking, what would I need to do on my
router?

Also, if I were to change only the subnet mask, again would I need to
reconfigure anything on my firewall or router?

Last but not least, I've heard conflicting info regarding the number of
hosts on a subnet. Can you pelase explain that further?

I always recommend never going beyond 254 hosts per segment. So I would
recommend creating an additional subnet using for example
10.10.1.1-10.10.1.255. You need to buy a Router to route between the
subnets (a "real" router, not an Internet Sharing NAT Device).

Whether or not you use DHCP is irrelevant to the issue.

If you don't want to add a subnet you could adjust your current Mask to:
255.255.254.0 You would have to change it on every machine.

This would give you the

10.10.0.0 - 10.10.1.255 which give 510 usable host.

But I still don't recommend going over 254, so the two subnets (254 hosts in
each) are still what I recommend.


--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com

My network addressing scheme can currently handle 254 hosts. The computers
are using static IP's rather than DHCP for security reasons. The scheme is
similar to the following: 10.10.0.1-10.10.0.255, Subnet Mask 255.255.255.0.


I need to add 50 hosts to my network within the next week and am out of
addresses. What would be the quickest, easiest, and most secure way to do
so?? Is DHCP the way to go?

 

[Phillip Windell]

Thanks for the input. Generally speaking, what would I need to do on my
router?

I can't tell you how to configure a router in an email. If you don't run
DHCP then you plug it in,...turn it on,...configure the interfaces of the
router.

With a single LAN Router with no redundant paths there typically are *no*
Static Routes, and *no* Routing Protocols. The router will be the Default
Gateway of every device on the LAN except for the Firewall/Proxy which
continues to use the ISP's router. The Firewall/Proxy will become the LAN
Router's Default Gateway.

The Firewall/Proxy will need a static route added to its own personal
Routing Table so that it knows where the other LAN Segments are on the
opposite side of the LAN Router. The Firewall/Proxy is unique in this
because it is the only machine on the LAN that does not point to the LAN
Router as the Default Gateway.

If you use DHCP you need a separate distinct Scope for each subnet on the
DHCP (No Superscopes!). The LAN Router will need to forward DHCP Queries
(typically called "helper addresses") so that Hosts on the opposite side of
the router from the DHCP can still find the DHCP.

Also, if I were to change only the subnet mask, again would I need to
reconfigure anything on my firewall or router?

Yes,...every single device on the network,...every hub, switch,
computer,..everything.

Last but not least, I've heard conflicting info regarding the number of
hosts on a subnet. Can you pelase explain that further?

That is because there is no exact number. You will *always* get conflicting
info. Ethernet is "broadcast intensive", it is how ethernet works. The
more hosts on a segment, the greater the amount of broadcasts,..the more
broadcasts, the more bandwidth is eaten up even before you actually *use*
the network. Broadcasts are limited for the most part to subnets (they
don't normally cross routers),...the less hosts on a subnet, the lower the
effect of the broadcasts.

When studying for the CCNA I always heard the range of 250-300 hosts was the
point where Ethernet typically begins to degrade. Since a 24bit Mask (class
"c") gives you 254 host,..that makes the 24bit Mask a neat, clean, way to do
it that keeps things very simple to deal with.