Network Security question

If there is a connection to the outside world from the network, the answer is yes.

If you access the internet from the orginization, you have at least a dymanic IP address everytime you log in to the ISP.

If you maintain a constant connection,you functionally have a static IP address.

Ahacker can get in through trojan programs attached to e-mails, or other software.

Chas

yes.
do you have a router? bet it's got an external ip address...do you telnet into it? is it password protected? what is it allowing thru?
good reading: "hacking revealed"
check out www.cert.org for easy tips on protection specific to your os.
my list of three things at the very least to do:
1) keep your antivirus software up to date
2) keep your Windows critical updates up to date
3) use 'tiny firewall' or some such free software firewall
be aware also of these possible other holes explosing your network (by no means a definitive list):
modems set to 'auto-answer'
remote control software, like pcanywhere
wireless access points...

Yes, it can be done via modems. If you don't have any external presence (no routers, no modems -- just hubs/switches and computers), then there are other methods of attack as well -- namely "Physical access" (you can be hacked from someone carrying in a floppy and booting from it on an internal computer connected to your LAN).

Question is why would anyone bother with you? Most of the reasons people give for hacking is to use your resources (ie mail relay, use hdds as storage space) or tocause you trouble (ie just because they can or if they have a personal vandetta). But for a non-external LAN, most hackers wouldn't normally be interested.

Yes, but having good firewall and antivirus solutions and a good IT manager who knows what is happening all the time is a good start to defeating these troublesome invaders.
:)