Re: [gentoo-user] Printer Sharing with Samba

[John Jolet]

> Question: how does one *make* a static IP? I thought that IP was
> assigned by DHCP? Isn't that the way that DHCP works? It leases an IP
> to a specific computer, which then gives up that lease when it's done
> using it. At that point, DHCP is free to re-lease that same IP to
> whomever else requests it, correct? If that's the case, what would
> prevent another computer from accidentally obtaining that same IP?
>
> Otherwise, if this is a viable solution, how do I make it work? I'm
> comfortable editing config files, but I just don't know where to go
> to do it.
>
> Thanks again, all, for your help.
>
> Kris
this is a more complicated question than it appears.  Let's say, for  
instance that you have an actual dhcp server, not just a router/ap  
giving out ips.  Now, most dhcp servers allow you to either  
statically, or dynamically, associate an IP with a MAC address  
(hardware address).  I can set my dhcp server up such that you ALWAYS  
get the same ip address for a given mac address.  This is helpful in  
some cases where you have more ip space than machines and want to  
know who gets what.  I can either do that by manually adding the mac  
into the configuration, or by making an infinate lease time.  in both  
cases, you've got a static dynamic address :)

if you have more machines than ip space (a class C subnet has on the  
order of 254 possible addresses), you have to have dynamic dhcp for  
those.  in that case, you have a much shorter lease time, and when a  
box comes on, it asks for the last address it has, and the dhcp  
server says "yes" if no one is using it, or "no, use this one" if  
it's in use.

however, IP is NOT limited to using dhcp.  you can manually set your  
machine to have a given ip address (since this is the gentoo list,  
it's in the /etc/conf.d/net file).  if you're manually setting an ip  
address, you do have to be careful that you're not setting it in the  
range that the dhcp server will assign.

email me offline if you need more detail than that....ip theory in  
general is a little off-topic.
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