For dummies guide to enabling DHCP on eth3, eth4, eth5 and eth6

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06-10-2010, 07:12 PM
ascorbic

For dummies guide to enabling DHCP on eth3, eth4, eth5 and eth6

I have a bunch of extra NIC ports on my Untangle box that I would like to plug computers into in order to have Untangle act as their router and gateway (where eth0 is WAN).

Can someone please give me a "for dummies" guide on how to accomplish this? I know DHCP will be needed. I don't know if I need NAT in the case, but if I do, please tell me what routes will need to be set up. Are there bypass rules which need to be changed? Are there packet filter rules which need to be changed?

My current Untangle configuration is very tangled. Instructions from a fresh install of Untangle in router mode would be awesome.

Thanks
06-10-2010, 07:18 PM
dwasserman

The wiki is very clear and orderly, I suggest read it
06-10-2010, 07:25 PM
ascorbic

I've gone through and through the wiki and I don't see instructions for this. I have seen pages which mention this can be done, but no instructions. If you could direct me to a link which directly shows how to configure this I would greatly appreciate it, I haven't been able to find it.
06-10-2010, 07:48 PM
sky-knight

There is no way to enable DHCP on anything other than Internal and DMZ.
06-10-2010, 07:48 PM
dwasserman

For dhcp
http://wiki.untangle.com/index.php/D...ver#About_DHCP

For Untangle your tangle box :-)
http://wiki.untangle.com/index.php/I...Configurations

For fresh install search quick install guide pdf
06-10-2010, 07:54 PM
ascorbic

Quote:

Originally Posted by dwasserman

For dhcp
http://wiki.untangle.com/index.php/D...ver#About_DHCP

I have seen and read through this. This guide tells you what DHCP is and how to configure certain options off DHCP. This does not tell you how to get DHCP working on interfaces other than Internal.

Quote:

Originally Posted by dwasserman

For Untangle your tangle box :-)
http://wiki.untangle.com/index.php/I...Configurations

For fresh install search quick install guide pdf

This doesn't have anything about DHCP.
06-10-2010, 07:56 PM
ascorbic

Quote:

Originally Posted by sky-knight

There is no way to enable DHCP on anything other than Internal and DMZ.

What is the purpose of Untangle supporting up to seven physical interfaces? What will the other four interfaces be used for?

http://wiki.untangle.com/index.php/Networking_Basics
06-10-2010, 08:07 PM
dwasserman

DHCP is a plus for very small network that dont have internal basic services like dhcp,dns,etc.
If you talk about a network with many subnets, sure this services are pre-existing to the entrance of untangle in this network.
06-10-2010, 08:11 PM
ascorbic

Quote:

Originally Posted by dwasserman

DHCP is a plus for very small network that dont have internal basic services like dhcp,dns,etc.
If you talk about a network with many subnets, sure this services are pre-existing to the entrance of untangle in this network.

Ok, I guess I don't fully understand that statement but DHCP would be a huge plus if I could get it working on my additional interfaces. Following that routing traffic to the internet would also be a plus.

So help or guides in order for me to get those pluses would be ideal.
06-10-2010, 08:15 PM
dwasserman

As said at top sky (and the wiki) no way. Only internal and Dmz
06-10-2010, 08:16 PM
sky-knight

Ok allow me to clarify...

You CAN enable DHCP support on all interfaces. But to do so you must disable the system packet filter rule that prevents DHCP access on all interfaces.

At this time there are packet filter rules built in to manually allow access to the local DHCP server for Internal and DMZ. There are no other rules for the other interfaces. I've tried many times, and never managed to get a GUI based custom rule to work. This is due to some special things that IPTables must be configured for to pass DHCP successfully.

So you CAN enable DHCP on everything, but in the process you're going to allow DHCP access on your External interface. Which is in a word... bad.

So I should say, there is no secure way to enable DHCP on interfaces other than Internal and DMZ.

And there are many reasons to enable other interfaces that don't involve DHCP. Remember, a proper DMZ shouldn't ever have DHCP on it anyway. As a DMZ should be populated by servers only. It all depends on what you're planning on doing with a given network segment. Not all network segments are created for use by network clients.

P.S. don't poke at IPTables directly, you'll only get frustrated when your settings get nuked every 15 minutes.
06-10-2010, 08:17 PM
ascorbic

Quote:

Originally Posted by dwasserman

As said at top sky (and the wiki) no way. Only internal and Dmz

Then why did you point me to the wiki, it doesn't explicitly state this is not allowed? And why does Untangle support seven interfaces? What use do the other four have?
06-10-2010, 08:22 PM
ascorbic

Quote:

Originally Posted by sky-knight

Ok allow me to clarify...

You CAN enable DHCP support on all interfaces. But to do so you must disable the system packet filter rule that prevents DHCP access on all interfaces.

At this time there are packet filter rules built in to manually allow access to the local DHCP server for Internal and DMZ. There are no other rules for the other interfaces. I've tried many times, and never managed to get a GUI based custom rule to work. This is due to some special things that IPTables must be configured for to pass DHCP successfully.

So you CAN enable DHCP on everything, but in the process you're going to allow DHCP access on your External interface. Which is in a word... bad.

So I should say, there is no secure way to enable DHCP on interfaces other than Internal and DMZ.

And there are many reasons to enable other interfaces that don't involve DHCP. Remember, a proper DMZ shouldn't ever have DHCP on it anyway. As a DMZ should be populated by servers only. It all depends on what you're planning on doing with a given network segment. Not all network segments are created for use by network clients.

P.S. don't poke at IPTables directly, you'll only get frustrated when your settings get nuked every 15 minutes.

Thanks for the clarification. I wonder why the developers went this route. This seems to greatly limit the functionality of Untangle. Why can't I just have one device for my small network? It sounds like Untangle really wants you to have a setup where your machine has two or at the very most three nics and a switch for all other traffic. I don't want to have to worry about this extra switch.
06-10-2010, 08:23 PM
dwasserman

For networking pourposes (external, internal, dmz) but without dhcp service
Untangle is an UTM software to protect your network, dhcp service is a residual plus to small networks, but not the main function.
Maybe, if you talk us about your network and your needs, can help you better.
06-10-2010, 08:35 PM
sky-knight

Untangle is a UTM appliance that targets the SMB. This imposes an "ideal network" model that the product supports beyond all else.

This "ideal network" model comes in three parts.

Internet - UT Router - LAN
Internet - Router - UT Bridge - LAN
Internet - UT Router - LAN & UT Bridge - DMZ

Yes the product supports 7 interfaces, and I happen to have a server in service with 6 active interfaces. 2 WAN, 4 LAN. 1 LAN is for the public wireless, the second is for the primary network, and 3 & 4 connect to other facilities via direct connections.

I don't need DHCP on that device at all, and one could argue that if you need Untangle to be a core router, and provide DHCP services to that many lan segments you've either designed the network incorrectly, or you're too big for Untangle.

If there is a feature Untangle needs to properly address this concern, it's a DHCP relay.