The famous ASA5505

I see many posts on the ASA5505, many answered and a few unanswered.

I'm curious to know how people set them up with dynamic IP's? I'm pretty sure not everybody is lucky enough to have a static IP address. Are people just inputting there current ISP given dynamic IP and changing it on the firewall as the ISP generates a new one? If so, that means that the entire network will be down for that "x" amount of time until you change it.

On a PIX firewall, you can change the IP accordingly but of course you will experience downtime. I know many people use the ASA5505 as there primary firewall, so I'd be curious to know how they handle it.

Using the Fortinet Fortigate firewall product line, you are required to enter the IP/Netmask which only the ISP can provide. Is this valid? I would think you could just figure out the netmask on your own. This is also dealing with the notion of dynamic IPs.

This is a deciding factor for both my friend and I purchasing ASA firewalls. I hope to have a static IP one day, a block of 8 would be nice, but until then I have to deal/manipulate/run-around/make use of dynamic IP's.


Cheers,

ZiPPy

You can have the ASA create the default route based on DHCP, so it should change with the dynamic IP.

Your config in the ASA would look something like this....

interface Vlan2
nameif outside
security-level 0
ip address dhcp setroute (<---What your looking for)

Then the Interface

---

interface Ethernet0/0
switchport access vlan 2

also, when referring to an interface IP (eg vlan2), use the keyword 'interface' instead of an actual IP address.