Outside interface cannot obtain newly assigned DHCP address

[Nigel Ng]

Hi Cisco Guru,

I'm currently using FPR1K running FDM code with outside interface is DHCP. However, since our ISP subscription is dynamic IP and they may sometimes force to renew a new IP and when this occur, my FPR will keep the old IP even disable and enable interface, unless, reboot or change the interface to PPPoE and revert to DHCP.

Do you guys have any suggestion on the configuration?

Thanks,

Nigel

[Muhammad Awais Khan]

Hi Nigel,

Usually dynamic IP from ISP will not change untill DHCP lease got expired

How do you know that your IP is change from ISP and Firepower is keeping the same IP ? Did your Internet got stopped working and that force you to restart the Firepower to get the new IP ?

I beleive whenever you restart or reboot your device, your interface with DHCP enabled will try to contact your ISP for the IP Assignment, if that time DHCP server from ISP side will either assign the same IP or different based on their setup.

** Please mark above as helpful or accepted as solution if it helped you out

[Nigel Ng]

Hello Khan,

Thanks for your prompt response.

Our provider really do that crazy thing, force you to renew with new IP after a period of time. I found my internet from dropped in a sudden, checked the outside interface still holding the previous IP even disable and enable the port. Then I changed the outside interface to PPPoE and change back to DHCP without restart the box and got a new IP.

Regards,

Nigel

[Muhammad Awais Khan]

Yes thats weird, didnt accross situation like this. Cant find much options in FDM about it.

Will see for comments or suggestions from other experts in this forum

[balaji.bandi]

ISP side IP allocation do not have control, depends on the DHCP lease time and expiry policy, since you are reconnecting very short time, you should get same IP address.

if that is changing - then you need to contact ISP - but most of the ISP willl not change for short term disconnections.