Weird IPs with my DSL service

[LS20]

I have verizon DSL with dynamic IP and have used 3 different network cards with that service: DLink , built-on SIS, and built-on Davicom.

the thing is, no matter how many times I reconnect/disconnect (release/renew), I will always get the same IP address.

if i switch NICs, though, I will get a unique IP.. but that IP will always remain static.


ie:

DLink: x.x.x.6 no matter what
SiS: x.x.x.12 no matter what
Davicom: x.x.x.27 no matter what


It's no bothering me, but I would like to know the explanation for this.

 

[n0cmonkey]

If you leave a particular card unplugged for a while, or the isp loses power you will get a new ip. dynamic doesnt mean you get one frequently. Works the same way on my verizon dsl, which is good for remembering what ip to ssh into

 

[Hobbzilla]

From my knowledge & experience I will continue to get the same IP when my DHCP lease expires. If I shut my computer down and start it back up.. 99.999% I get the pre-shutdown IP. If it is off for 2+ days I find 75% of the time my IP doesn't get changed. Now, I have cable with it uplinked to my hub issuing 2 IP's to both my pc's.. My IP's first 3 octets have been the same on my machine. On my wife's the 3rd octet is different then mine that I have seen. Now from my understanding my cable provider authenticate's me by my cable modem's MAC vs. DSL & their PPPoE. However, I am fairly confident that they release my Dynamic IP's based on my NIC's MAC. Not that they have a table that says ohh.. a 3com nic gets x.x.x.x while the ibm gets the x.x.x.x. I'm saying that once your NIC's MAC requests an IP it DOES keep a table of requests and IP's issued. And more likely than not if you disconnect and that NIC re-requests an IP via DHCP the DHCP server knows what IP it gave them last time and if it is available just issues the old one back to it. By no means is this exactly what happens.. I did not program BIND or DHCP or any other protocol. It is just an explanation of my experiences.

 

[n0cmonkey]

I have used linksys nics for my dsl. 3 different ones I believe. I got a different ip with each one. When I left my machine unplugged for a week (havent tried shorter periods) I got a new ip address. All of the ips I got were in the 4.60.0.0 range. The third octet was frequently different, but not far off from the others. I havent checked the other machines on the same dsl line so I dont know whats up with them.