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Strange SMTP issue between ISA and Barracuda - 27.Jul.2004 8:20:00 PM

setlou

Posts: 2
Joined: 27.Jul.2004
Status: offline

I'm having a problem relaying email through our new ISA 2004 box.

I've published our internal SMTP Server.

If I telent to the external IP address if the isa box it forwards me to internal server. I can then manuially type in the commands and send emails to users of the server with no problem.

When I try and set our barracuda 300 to relay throught the ISA box it get connection denied.

If I forward through another firewall it works just fine.

We need the barracuda because we filter around 200k in spam everyday

I've tried setting it up as server to server client access, and I've even gone as far as creating a new port 25 to see if that would work.

Post #: 1

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RE: Strange SMTP issue between ISA and Barracuda - 28.Jul.2004 1:24:00 AM

tshinder

Posts: 47659
Joined: 10.Jan.2001
From: Texas
Status: offline

Hi Seth,

Does the log say what rule denied the request?

Is the barracuda forwarding to the IP address on the external interface of the ISA firewall? That is, the IP address that you used for the listener in the ISA firewall's SMTP Server Publishing Rule?

Thanks!
Tom

(in reply to setlou)

Post #: 2

RE: Strange SMTP issue between ISA and Barracuda - 28.Jul.2004 3:15:00 PM

setlou

Posts: 2
Joined: 27.Jul.2004
Status: offline

Yes I'm forwarding to the external IP address on the ISA box from the barracuda.

The wierd thing is, when I search the logs for connections on port 25 I see absolutly nothing coming from the barracuda.

When I do the telnet to port 25 I actually see the Connection initiated in the logs.

This would lead me to believe it's a routing or firewall issue at the ASP it's located at, but every other addresses in the block the ISA box is in is reachable from there.

I triple checked my rules on the pix the barracuda and telnet are coming through and they are allowing the traffic. "I only allow port 25 out from the box I telneted from and the barracuda" Also the box I'm telenting from and the barracuda use the same gateway. It's a PIX 515E. So both connections should appear to come from the external IP address on the PIX to the ISA box.

I have the exact same setup running through an ISA 2000 box to another location. Should be easy stuff to setup that's why I'm so baffled

If Barracuda would give me the root logon to the box it would make life much easier.

Edit: I have a call into Barracuda Networks regarding this to see if it's an actual issue with thier device. I'll post the results of the call.

[ July 28, 2004, 04:52 PM: Message edited by: Seth ]

(in reply to setlou)

Post #: 3

RE: Strange SMTP issue between ISA and Barracuda - 29.Jul.2004 6:25:00 AM

Uju Sivas

Posts: 236
Joined: 31.Dec.2001
Status: offline

Any smtp / mail related issues, needs to talk thru smtp access rule in mail server publishing...
I think it is top one....try with that...

(in reply to setlou)

Post #: 4

RE: Strange SMTP issue between ISA and Barracuda - 29.Jul.2004 3:29:00 PM

tshinder

Posts: 47659
Joined: 10.Jan.2001
From: Texas
Status: offline

Hi Seth,

If you don't see the incoming SMTP connections from the Barracuda box to the ISA firewall, then that could be it. Is the PIX packet filter forwarding the connections from the Barracuda box to the ISA firewall? Do you see the connection from the Barracuda box hit the WAN interface of the PIX packet filter?

Thanks!
Tom

(in reply to setlou)

Post #: 5