DHCP servers will attempt to reassign the same IP address to the same
MAC address by maintaining a list of leases. On a home network you
should generally be getting assigned the same IP every time. It would
only change if you start adding some more machines and it runs out of
unused addresses or the lease time had expired. So if you haven't
plugged your machine in for a while you might not get the same IP again.
The lease length default varies from router to router. Some will let you
configure it. If it is configurable I'd set it to something like 30 days
on a home network. Maybe a week for an office network.
CB
Jane Lee wrote:
Whoops, my message was a bit too long, lemme try this again:
Hi Chris and others (from the other jane, not the one asking):Some routers
have software (well, I want to call it dnsmasq but I forgot the name) where
it basically maps a semi-permanent IP based on a mac address. No need to
configure it to be static, it's all done by the router. If your router falls
under these (mine does, it's a linksys wrt54gl running dd-wrt), the DHCP
assigned address will not change for the device even after reboots.
Also it's worthwhile to point out that to access your computer via ssh from
another computer you *need* to forward port 22 or whatever you're using for
ssh. You also need to know your IP address. Alternatively, your router might
have software that works with no-ip.org or dyndns to provide a redirection
service - e.g. no need to remember something like69.138.19.233 when you can
have yourname.dyndns.org instead. This doesn't really compromise anything
the IP doesn't already. Just have a sensible password, don't give it out to
anyone. If you're slightly paranoid about that, set up ssh keys with a
different passphrase. Then the attacker *must* have the key and the
passphrase to do anything. If you still can't trust it, don't ssh at all,
hehe.
cheers,
jane
