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How do I open ports to the untrust interface on a Juniper SSG-140?

We have a Juniper SSG-140, I know how to create MIPs and open ports to those MIPs. However I can't seem to figure out how to open ports to the default IP of the untrust interface.

Sanga Collins

the default ip on the untrust interface can only be mapped to another internal IP using a VIP (virtual IP) the process to setup a VIP is very similar to the setup for a MIP. If you need help with specifics or run into problems, please post :)

ThorinO

ASKER

To be more specific, what I am trying to do is open a few ports incoming (untrust) to 2 IPs on the trust side. I know how to do this on a MIP but not on the untrust IP.

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Sanga Collins

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Sanga Collins

you can not create a MIP on the ip assigned to the untrust interface, but you can create a VIP

ThorinO

ASKER

OK thanks, I will give this a try, I assume that like with the MIP that creating a VIP won't interrupt traffic assuming I do it correctly?

Sanga Collins

Yes you are correct. If configured correctly the process will not interrupt inbound or outbound traffic. I have created temporary VIPs for my corporate office in the middle of the day without any issues at all.

ThorinO

ASKER

OK so I followed the guide, I created the custom services, created the VIP to the untrust IP and mapped it to the IP of the desktop I want to allow the ports to go through to. I created a policy from any to the VIP with the 3 services I created.

It is still not working, I did not do #4 as I assume it has to restart the firewall? Do I need to do step 4 for this to work?

Sanga Collins

Yes you must enable multiport VIP if you are mapping more than 1 ip address to an internal server/desktop.

ThorinO

ASKER

If I am just using the untrust IP do I need to do this? If I already have multiple VIPs would this already be enabled?

Do I have to reboot the firewall to enable this?

Sanga Collins

You do have to reboot the firewall for the change to take effect. If you have other VIP with multiple ports then its probably enabled. But if you have MIPs, then the setting does not apply. VIPs and MIPs even though they do the same thing are handled differently by the device.

ThorinO

ASKER

How about if I can get away with just 1 port on the VIP, can I get it working without the reboot?

Would this be why it isn't currently working?

Sanga Collins

Yes if you only forward one port in the VIP, you can get away without setting up the multi-port option. I often test with one port first before enabling the multiport.

ThorinO

ASKER

Cool, I will try that, would I be able to go to 2 desktops with just 1 port without the reboot?

Sanga Collins

you can not forward the same port to two different desktops. Port forwarding is a 1 to 1 mapping. for example i can not forward RDP port to two different computers.

ThorinO

ASKER

Can I open the port globally to the untrust interface?

Sanga Collins

No, with port mapping you must specify a target workstation/server on your local network. you can not open up a port to nowhere since ti defeates the purpose of a firewall.

ThorinO

ASKER

For some reason it was not working when I was testing with 1 computer. We are running firmware 5.4.0r1a.0 . Attached are the screenshots of the VIP, policy, and service I have defined. I verified that the target system firewall is off as well.

ThorinO

ASKER

I also just saw this in the alarms: crit VIP server 10.100.0.65 cannot be contacted.

I verified that I can ping it and the other day I had him verify his IP.

Sanga Collins

In the VIP configuration, turn off the option for server auto-detection. Ive noticed with that enabled. for some reason the device disables the VIP if it can not detect the server on the LAN. This would be ok if when the server is online the check passes, but even on screenOS 6.2 it always fails!

BTW i noticed your services are for SC2. I am surprised you would need to go through all this just to play or update SC2 on your PC. I have SC2 myself and play on both PC and Macintosh without having to do anything special on the firewall.

Something that might help is source based translation.

got to policy and choose your main outgoing policy (trust to untrust) and select edit, then advanced. At the top enable

Source Translation (DIP on) None use eggress interface IP.

basically what this does is make sure that traffic from your SC2 workstation has the correct info so that the return traffic makes it back to the PC. It also helps with VOIP phones (which is where i learned the trick)

ThorinO

ASKER

I unchecked the detection box and it still did not work. I am going off of the following: http://us.blizzard.com/support/article.xml?locale=en_US&articleId=34063

I have not tried the outgoing policy change as I don't want to affect anyone else if something goes wrong.

I'm not sure why the connection isn't working though. I have this person in an outgoing policy that allows any and I have the firewall setup correctly to allow port 1119 incoming :*(

Sanga Collins

Ah i see now. For the service 'StarCraft II' add UDP port 1119 in addition to TCP 1119, and on the outgoing policy for the users computer add the source based routing i mentioned in my previous port :)

ThorinO

ASKER

Do you think the outgoing policy change will affect anything? There are multiple users (and servers) on this policy and I don't want to break anything for the sake of SC2 ;)

Sanga Collins

you can always create a single policy for the user that wants to play SC2. Just make their IP the source ip address of a trust - untrust policy. In the advanced options of the policy, enable source translation.