topic Re: DHCP Fail in Next-Generation Firewall Discussions

DHCP Fail

Alex_S — Mon, 28 Nov 2022 21:24:15 GMT

Hello Community,

I have a FW with eth0 configured as DHCP client and it gets IP, no problem. But then I see lots of DHCP Fail system messages between lease renewals:

Are these normal?

Thanks!

Re: DHCP Fail

Metgatz — Tue, 29 Nov 2022 06:03:11 GMT

Hello @Alex_S

Hi, I have not had that specific error, but when you configure the DHCP server in the PA, you have the mode enabled or AUTO.

When it is in Auto the DHCP polls if there is any other DHCP Server on the network the PA downgrades the DHCP service.

Do you have another DHCP server in conflict in your network ?

Regards

Re: DHCP Fail

Alex_S — Tue, 29 Nov 2022 13:24:12 GMT

Thank you for your reply @Metgatz

The interface in question (eth0) is configured as DHCP client. I think the setting you're referring to is for DHCP server config. I do have eth1 configured as DHCP server but the messages point to eth0 not eth1

Re: DHCP Fail

Metgatz — Tue, 29 Nov 2022 19:00:57 GMT

Hello @Alex_S Ok, I understand, thanks for the clarification.

Is it mandatory that you use DHCP ? Why don't you reserve an IP from that range, so that it is not assigned to anyone, that DHCP delivers, set the IP on the interface, add the static route with the next hop. Of course if you allow it, if you use DHCP with PPPoE, normally it can be a bit more complex to identify or set an IP and route, however if that DHCP range is from an operator like a 4g Modem/Router or is a range that you control, then you could set the IP, instead of using DHCP.

Regards

Re: DHCP Fail

Alex_S — Wed, 30 Nov 2022 14:22:33 GMT

@Metgatz This is a shared office environment at a remote location that's only accessible via IPSEC thru the FW. I cannot risk assigning an IP from the range I cannot control (it's controlled by another company). What's interesting is another FW in the same office space but different IP range (different floor) doesn't have this issue.