Your only option is to add another mail server for sending mail that also has a userlist to authenticate (many possibilities here depending on the MTA). The new sending mail server could be configured to send it's mail through the Barracuda. Then on your IMail machine, use the control access list to only accept connections from the Barracuda.
Otherwise, as Len put it. They will scan for an available port 25 and try connections to it regardless of any DNS entry or lack thereof.
john
Darin Cox wrote:
I would say most definitely.... depending on the firewall, it might even block some of the DOS attacks itself. I use and like Cisco Pixes, but administer a lot of SonicWalls...good bang for the buck with them.
Darin.
----- Original Message ----- From: "Grant Griffith - IMail" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, March 11, 2005 1:28 PM
Subject: RE: [IMail Forum] Need Help Preventing Connections
Guess the answer is to throw a firewall up then? I have been going to do that anyway.
Thanks, Grant Griffith EI8HT LEGS, A Division of ETC (877)483-3393 (812)933-5390 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Darin Cox Sent: Friday, March 11, 2005 1:14 PM To: [email protected] Subject: Re: [IMail Forum] Need Help Preventing Connections
I think part of the issue is that the IMail server is still publicly available via SMTP, so spammers can still send through it even though it's not listed in DNS as an MX.
Darin.
----- Original Message ----- From: "E. Shanbrom (Ipswitch)" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, March 11, 2005 1:08 PM Subject: Re: [IMail Forum] Need Help Preventing Connections
Use the relay for addresses and put the Barracuda address in there. MAKE SURE the Barracuda machine will only forward mail destined for your domain(s) or you WILL end up an open relay as IMail will relay for anything coming from the Barracuda.
Eric S
----- Original Message ----- From: "Grant Griffith - IMail" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, March 11, 2005 8:32 AM
Subject: [IMail Forum] Need Help Preventing Connections
Hey All,
We have a Barracuda Firewall in front of our Imail server and I want to setup Imail so that only Authenticated users and the Barracuda can connect to Imail and send messages. How do I go about setting this up in Imail?
Do
I need to Deny Access to everyone except my barracuda in the Control
Access
area in SMTP security? Does that still allow my users to authenticate and send messages?
Thanks all for any help. I am just trying to stop all the DOS Attacks we have been getting.
Thanks, Grant Griffith EI8HT LEGS, A Division of ETC (877)483-3393 (812)933-5390
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