How to force DHCP client router to renew its lease?

How to force DHCP client router to renew its lease?

Post by JohnH » Mon, 06 Feb 2006 00:49:51



Hi,

        I have a Cisco 2514 acting as an Internet gateway in a CCNA study lab
setup.  I have a Comcast cable modem connect to e1.  The 2514 is
configured as a DHCP client to get its IP addressing info from Comcast.
 This all works fine.

        Occasionally when I change configurations in the lab I want to force
the 2514 to renew its DHCP lease info from Comcast.  The only way I
have been able to do this is to power cycle the cable modem. Then
"shutdown", "no shutdown" interface e1.  Simply shutting down
the interface and bringing it back up does not cause the router to get
a fresh IP address on e1 unless I power cycle the modem first.

        Is there a better way to do this?  It seems to that there would be a
direct unambiguous command to renew the DHCP client, something akin to
"ipconfig /renew" in windows.  But, I'm new to this and may not
be thinking in the correct context.

Thanks,
John

 
 
 

How to force DHCP client router to renew its lease?

Post by Martin Bilgra » Mon, 06 Feb 2006 04:00:56



Quote:> Is there a better way to do this?  It seems to that there would be a
> direct unambiguous command to renew the DHCP client, something akin to
> "ipconfig /renew" in windows.  But, I'm new to this and may not
> be thinking in the correct context.Not sure about 2500's, but other CIsco

IOS router, you can go into conf-t mode under the interface and simply
re-issue the "ip address dhcp command"
This will then, as it is in running config, get excecuted at once.

Try it, and give a yell, if its ok or not.

HTH
Martin Bilgrav

 
 
 

How to force DHCP client router to renew its lease?

Post by JohnH » Wed, 08 Feb 2006 08:35:05


Thanks, that did it.  i copied the "ip address DHCP..." command into
the clipboard, entered "no ip address."  I then pasted the ip address
dhcp command back from the clipboard hit enter and a new IP address was
recieved from the ISP right away.
 
 
 

How to force DHCP client router to renew its lease?

Post by Martin Bilgra » Thu, 09 Feb 2006 03:33:53


no need to say "no ip address" first, just simply re-issue the "ip address
dhcp"

HTH
Martin


Quote:> Thanks, that did it.  i copied the "ip address DHCP..." command into
> the clipboard, entered "no ip address."  I then pasted the ip address
> dhcp command back from the clipboard hit enter and a new IP address was
> recieved from the ISP right away.

 
 
 

How to force DHCP client router to renew its lease?

Post by JohnH » Fri, 10 Feb 2006 01:21:40


Thanks for the tip!
 
 
 

1. Mac/RoadRunner "Cannot renew DHCP lease" - HOW DO I GET RID OF THIS MESSAGE???

I use Macintosh OS 8.6 with a cable modem that required TCP/IP configured to
"DHCP". Everything works fine, EXCEPT that every 15 minutes or so I get a
dialogue box stating

"CANNOT RENEW LEASE WITH DHCP SERVER. ANOTHER APPLICATION IS USING THE DHCP
PORT. CONTACT YOUR NETOWRK ADMINISTRATOR"

EVERY 15 MINUTES!!!

My cable connection is just fine, it is renewed. I use RoadRunner which
requires a login program - I presume that is the "other program usimg the
DHCP port". Isn't there someplace to tell the Mac it doesn't NEED to try to
renew the lease??

Wasn't a problem with 8.5.1. When 8.6 first came out I remember hearing
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