Possible to automatically renew DHCP?

[horinius]

Hi,

I have a FortiGate 80c (firmware = 4.3.15).

Its WAN2 is connected to an ADSL modem and the IP address is acquired through DHCP from the modem.  This connection is a fall-back Internet access in case WAN1 has problem, so IP traffic through it is very very few.  Maybe that's the reason why it always lost IP address every few days.  Yeah, I check the interface once every three or four days.  Most of the time when I open Network > Interface, the IP/Network column for this interface is 0.0.0.0/0.0.0.0.  And every time I have to "edit" the interface and click the "Renew" button to acquire the IP address again.

It seems like FortiGate "forgets" to request IP address after expiration date when there's no IP traffic.

Is there any way to make Fgt 80c request IP address from time to time?

Thanks

[emnoc]

I doubt that & had problems before with a fortigate and DSL provider ( century link ) , but here's what you can do to prove this;

1: install the modem on a window-server or linux-server runing dhcp services

2: adjust the lease time to a low value and make sure the unit maintains the lease

If the unit maintains the dhcp lease and  request/ack than it's not the  fortigate.

note: If your in a pinch you  and have multiple interface, you could build 2 vdoms with a single interface in the vdom and server the 2nd vdom interface  for testing using the dhcp-server of the fortigate

e.g

vdom == Server ( services the dhcp services )

vdom == Client ( is the dhcp client )

config sys int

   edit    port1

        set vdom "Server"         set ip 192.0.2.1 255.255.255.0         set allowaccess ping https ssh snmp         set ident-accept enable         set type physical         set alias "dhcp-server"     next

        edit   port2

        set vdom "client"         set mode dhcp         set allowaccess ping https ssh snmp         set ident-accept enable         set type physical         set alias "dhcp-client"     end

and now the dhcp-server;

config system dhcp server     edit 1         set default-gateway 192.0.2.1         set interface "port1"             config ip-range                 edit 1                     set end-ip 192.0.2.100                     set start-ip 192.0.2.10                 next             end         set lease-time 300         set netmask 255.255.255.0         set dns-server1 8.8.4.4         set dns-server2 8.8.8.8

        set status enable     next end

And just sit  and monitor. Every 300secs the port2 interface will renew the lease from the dhcp-server in  vdom Server.

BTW: I'm running 4 mr3 patch18 with zero problems.

[horinius]

I don't understand what you meant by "install the modem on a window-server or linux-server runing dhcp services".  You want me to replace the modem with the window/linux server?  Or you want me to replace Fortigate with window/linux server?

Suppose it's the ADSL modem the source of the problem, what do you suggest me to do (without the VDOM-thingy that I don't quite understand)?

PS: I have just checked the connection and it is already down again!  This time ADSL connection only lasted two days!  That's a new record.

[corymrussell]

Does power cycling the modem hand out a new address or do you still have to click renew? If you have the testing ability to do so, do you have something else that can hand out DHCP addresses? Not ideal if you need a fail-over but plug that in to WAN2 and see if it drops the address. This way you can see if the problem replicates without the modem isolating the problem.

You also may want to call support on the DSL modem and have them check the leases. When it renews there may not be any available. Just a thought.

[emnoc]

I don't understand what you meant by "install the modem on a window-server or linux-server runing dhcp services".  You want me to replace the modem with the window/linux server?  Or you want me to replace Fortigate with window/linux server?

oops, I meant interface  directly. I'm so tie-up with modems(ADSL) ;)

Just cable the interface or any interfaces to a DHCP-SERVER and ensure it maintains  the lease. You could test this with any freed interface on the fortigate b4 you  bother the ADSL provider, but I'm guessing it's an ADSL modem issues like the above poster stated.

Is the ADSL-modem in a bridged or routed-mode?