Exchange 2010 OWA Ceases to Work With Transparent Proxy Enabled

NethServer Version: 7.7.1908
Module: Web Proxy & Filter

Hi Everyone,

Just experimenting with the Web Proxy & Filtering and the proxy works as expected but for some reason is blocking our internal SBS 2011 and Exchange server from delivering both the OWA and Remote websites.

The setup is as follows:
Nethserver:
IP: 192.168.8.11/24
Gateway: 192.168.8.1
DNS: 192.168.8.1

192.168.8.1 is our Mikrotik router.

SBS 2011 Server:
IP: 192.168.8.10/24
Gateway: 192.168.8.11 (The Nethserver)
DNS: 192.168.8.10 (SBS Server)

The browsing works as expected, just the IIS web services aren’t being delivered. Is it because it’s a transparent proxy and I need to apply some settings to the Nethserver to account for this and treat the SBS server differently?

If I change the Gateway of the SBS server back to the Mikrotik router, all the web services return to normal and work properly.

Any help and guidance would be most appreciated.

Thanks

Duke

How many interfaces has your NethServer setup?
Only one configured as green?

Hi pike,

Yes, just one set as Green. Is that an issue?

Thanks

Duke

If your NethServer only has 1 interface and that is configured as GREEN interface, it is not possible to use NethServer as gateway since it has no external interface to route the packets further.
If your Mikrotik is your router, then for all clients that should be the gateway.
What server is acting as account provider (is the SBS server or NethServer the account provider?)
What is acting as proxy? and how did you configure this?

Hi Rob,

This setup as I’ve outlined in the original post works flawlessly bar the SBS issues. Using Nethserver as the gateway is working even with only one interface.

The content filtering works using the NS as a transparent proxy. I understand your argument that it requires a second interface, but I assure you it works.

By account provider, I assume you mean for log on authentication? If that’s the case, then it’s SBS using active directory.

Duke

Hi Rob,

I’ve added a second NIC to the Nethserver, but still can’t get this to work. Can you please give me some recommendations as to how to set this up correctly?

At the moment I have the following setup:

Mikrotik Router:
Primary IP: 192.168.8.1/24 > This is the Green network
WAN: PPPOE
Secondary IP 10.0.88.1/24 > This is used as the Red network for Nethserver

Nethserver:
Primary IP: 192.168.8.11/24
Gateway: 10.0.88.2 > This is the Nethserver Red (Not sure this is correct but is still works from the Nethserver)
DNS: 10.0.88.1 > Mikrotik Red Interface

SBS 2011:
Primary IP: 192.168.8.10/24
Gateway: 192.168.8.11 > Nethserver Green
DNS: 192.168.8.11 > SBS Server

SBS 2011 uses the Nethserver (192.168.8.11) as the DNS Forwarder in the DNS settings.

I hope this makes sens. If anyone can shed some light on this, that would be great.

Thanks

Duke