# releasing DHCP IP address under 9.1



## dvl@ (Aug 25, 2013)

I'm replacing an existing gateway server with another.   The new server isn't getting an IP address from my ISP.  I suspect it's because I need to release the old IP address first.  I keep seeing references to the man page, and the -r option.  I suspect that information is out of date, because there is no -r option on dhclient any more.

It was suggested I could hack the new system, and give it the same MAC address as the old NIC, but that seems... so hackish.


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## wblock@ (Aug 25, 2013)

-r appears to have gone away with the import of dhclient from Open BSD 3.7.  FreeBSD 5.5 had the old version, 6.0 the new, without the -r option.

Seems like killing and re-running dhclient should do the same thing.  Maybe the ISP is assigning IP based on MAC address.


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## ondra_knezour (Aug 25, 2013)

The ISC dhcp client has an option for the lease release and is in the ports net/isc-dhcp42-client. However I will suspect a static DHCP assignation on the side of your ISP at first place.


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## dvl@ (Aug 25, 2013)

wblock@ said:
			
		

> Seems like killing and re-running dhclient should do the same thing.  Maybe the ISP is assigning IP based on MAC address.



I will try shutting down dhclient on the old gateway first. I was doing a shutdown -p now. I would expect that achieve the same thing.


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## dvl@ (Aug 25, 2013)

ondra_knezour said:
			
		

> The ISC dhcp client has an option for the lease release and is in the ports net/isc-dhcp42-client. However I will suspect a static DHCP assignation on the side of your ISP at first place.



I will try that too. However, I am quite sure that my IP address changes not infrequently. Often after a reboot, I'll get a new IP address.


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## dvl@ (Aug 26, 2013)

The procedure I just tried did not work: shutdown old gateway.  Reboot modem.  Power up new gateway.


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## wblock@ (Aug 26, 2013)

Have the gateway on before power cycling the modem, in case it looks for the attached system's MAC address.


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## dvl@ (Aug 26, 2013)

ondra_knezour said:
			
		

> The ISC dhcp client has an option for the lease release and is in the ports net/isc-dhcp42-client.



I tried `$ sudo /usr/local/sbin/dhclient -r fxp0`.

For those looking for the man page, try: `$ man /usr/local/man/man8/dhclient.8.gz`

But this didn't help the new gateway get an IP address.


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## jbeez (Aug 26, 2013)

You need to call Verizon and have them "release" the IP on their end. I've been through this several times. Just how FiOS works in our area.


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## ondra_knezour (Aug 27, 2013)

As the keyword Verizon appears - I saw an advice to put the modem offline for two hours to remove MAC - IP binding in the Verizon network during googling. However I was never closer to any Verizon service then couple of hours on plane board so I can't verify it.


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## junovitch@ (Aug 27, 2013)

Have you tried something like `# pkill dhclient && ifconfig fxp0 ether xx:xx:xx:xx:xx:xx && dhclient fxp0` where the old MAC is in there to at least prove that the MAC is the issue?  If the ISP is hard set to your old system's MAC address and power cycling doesn't clear that, setting the MAC to the old system may be the only way to get an address until you deal with their tech support and get it cleared up.


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## dvl@ (Aug 27, 2013)

Couple of hours?  Ain't nobody got time for that!


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## dvl@ (Aug 27, 2013)

junovitch said:
			
		

> Have you tried something like `# pkill dhclient && ifconfig fxp0 ether xx:xx:xx:xx:xx:xx && dhclient fxp0` where the old MAC is in there to at least prove that the MAC is the issue?  If the ISP is hard set to your old system's MAC address and power cycling doesn't clear that, setting the MAC to the old system may be the only way to get an address until you deal with their tech support and get it cleared up.



Yes, I added /etc/start_if.fxp0 sets the MAC. I'll post the file once I'm back in front of a computer.


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## dvl@ (Aug 30, 2013)

```
$ cat /etc/start_if.fxp0 
#!/bin/sh
/sbin/ifconfig $1 ether 00:04:ac:3a:47:af
```


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