Missing configuration options for DHCP?

[Randy Baker]

I had quite a nasty surprise with my Linux based DHCP server after applying the latest patches to it. My Linux based DHCP service will not start, so I thought I would enable the WinGate DHCP server. All is not well.

I need the equivalent functionality of the following /etc/dhcpd.conf parameter:

range 192.168.1.20 192.168.1.100;

I need to be able to configure the available range of IP Addresses that DHCP is allowed to issue. For example, I never want DHCP to issue DHCP addresses in the range of 192.168.1.1 through to 192.168.1.20, and I do not want any more than 80 guest devices on the network. That range of addresses are statically assigned to servers and network devices.

I also need the equivalent functionality of the following /etc/dhcpd.conf parameter:

host agora {
hardware ethernet 00:1A:92:B1:21:74;
fixed-address 192.168.1.200;
}

This allows specific known devices to be allowed on the network, but are not infrastructure devices, and are not to consume guest IP addresses in a limited range.

Any chance this functionality exists in the current product and I have just missed it, or it is functionality in the next version of WinGate? This isn't a big deal, as I just need to find out why my Linux DHCPD service is failing.

[Randy Baker]

I just discovered that right clicking the adapter icon under DHCP Settings allows me to create the scope, and to set a number of options for the scope.

There is still the issue of ensuring a specific MAC address is assigned a specific IP Address.

[logan]

What you are talking about is called a reservation. WinGate can hold certain IP addresses for clients with a specified computername or mac address. Here's a quick step-by-step on making a reservation.

1. Gatekeeper > System > DHCP > DHCP Settings

2. Right click on the scope that you want to make a reservation in and click "New reservation". A scope is indicated by a lightbulb followed by the ip range of the scope in square brackets.

3. Enter the IP address that you want to reserve, select Reserved for MAC Address, and enter the MAC address of your client computer that you want to hold this IP for.

4. Click OK, then Apply to finalise the change.

[Randy Baker]

Thank you for the update. I found it, configured it, but it isn't working properly yet.

- The online help identifies how to create a reservation, but there is no example to configure a MAC Address reservation. I initially copied the MAC address as entered in my Linux dhcpd.conf (00:1A:92:B1:21:74) and assigned it the IP address of 192.168.1.4. I went to the computer and performed an ipconfig/release, ipconfig/renew. The computer was reassigned 192.168.1.22. I then reverified the MAC address was correct, and tried the Microsoft MAC format of 00-1A-92-B1-21-74 and released and renewed the IP. The system still was assigned 192.168.1.22. I verified the DHCP server is the WinGate server, stopped and started the WinGate DHCP service, released and renewed the client, yet the client is still receiving the incorrect IP address.

I did not try other variants such as no separators, lower case hex, or other lesser used formats such as 001A.92B1.2174.

- I have enabled full logging for the DHCP service. However, I do not see any DHCP logging of value from the GUI to investigate this issue. Under History, I see DNS, HTTP, POP3 but no DHCP. I see under System, DHCP objects, the messages are (0604) "No acceptable offer can be made to client...". But the system in question is a W2K server whose 180 day eval license has expired that I have not reconfigured with another O/S yet.

- I did open the log file on disk and found more details. However, I noticed what I believe to be only the DHCP Offer and DHCP ACK logged. I am assuming the WinGate DHCP service is rfc compliant, so can the level of debugging be increased to include the Discover, Offer, Request and ACK? Also missing in the debug log is the MAC address of the requesting client and the network address the request originated on.

- I suspect, but cannot confirm yet, that when the DHCP lease expires, that is when the WinGate DHCP service might honour the MAC reservation.

Any ideas? Or, have I missed or misconfigured something?

Thank you.
Randy

[adrien]

Hi

I checked through the code, and it looks like it needs to have no separators at all, e.g. 001A92B12174

WinGate should refuse to allocate the old invalid IP if the reservation IP doesn't match.

Regards

Adrien

[logan]

I did some testing and discovered the following:

1. MAC addresses must be entered without seperators. i.e. instead of 00:00:00:00:00:00, simply enter 000000000000.

2. Reservations must be created within the IP range of the scope they are created in. Making a reservation for IP 192.168.1.14 inside the scope 192.168.1.20->100 will not work, whereas making a reservation for an IP inside the scope (e.g. 192.168.1.50) will.

Hope that explains things for you. If you wanted to make reservations in the 10's, you should lower your scope. If you don't want WinGate to assign ip's from the 10's to computers other than those with reservations, you can add the IP's that don't have a reservation associated with them to the exluded ip's list of the scope.

[Randy Baker]

Thanks for the update.

I modified the scope as you suggested to 192.168.1.10 to 192.168.1.100. I made the reservations in the .10-.20 range, and created an exclude list from .10-.20. This did not take effect until I stopped and restarted the DHCP service. But my reserved IP was assigned properly, and my guest workstation was assigned an IP in a range above the exclude list.

The documentation does not state that the DHCP service requires a restart to put the changes into effect. However, I have a laptop beside me for testing, so it is possible if it takes a minute or so for the changes to automatically take effect in WinGate, that I released and renewed before WinGate was ready.

[adrien]

Hi

Shouldn't require a stop/start. Stopping and starting a service in WinGate only affects the bindings / sockets - it doesn't reload any config or anything at that point (only when you restart WinGate).

In fact any change you can do in GateKeeper apart from disabling the ENS driver is (or should be) immediate.

So, I'm not sure what caused the delay in this case.

Regards

Adrien

[logan]

Just FYI, changes took effect immediately in my tests so what Adrien says is true.