forcing new dynamic ip address

Mike the.lists at
Sun Oct 8 15:04:35 UTC 2017

On 10/8/2017 8:28 AM, Ernie Luzar wrote:
> Hello List;
> I have a "home service" account from my ISP. The ISP issues an dynamic 
> ip address which has not changed in 12 years.
> My host has 2 NICs, one which is not used. I know if I plug the internet 
> cable into the un-used NIC and make the appropriate config changes and 
> reboot I will get a different dynamic ip address.
> Is there a simpler way to expire the lease to force the ISP dhcp to 
> refresh with a different dynamic ip address?
> The goal is to have a cron job that gets a different dynamic ip address 
> assigned to my host's front door every a week.
> Just another level of security to make it very hard for the script 
> kiddies from finding any open ports I may have.
> Thanks for the help.

I have a few old NICs that i keep, not because I need to use them, but
because i want to be able to use their MAC address.

Then I use one of the MAC addresses in rc.conf, e.g.,

ifconfig_em0="DHCP lladdr yo:ur:MA:C:ad:dr:es"

My ISP assigns a new IP address when the DHCP server sees a new MAC address.

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