RE: [IMail Forum] Solution to the 587 blues

[Robert E. Spivack]

T-mobile has a clever approach.  They don’t block port 25, but they dynamically remap it to their own outbound smtp server.  Actually a very nice method – seems to be transparent to both the end-user and the host and works without any special reconfigurations while providing anti-spammer protection against relaying.   From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jonas Fornander Sent: Wednesday, July 13, 2005 9:37 AM To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Solution to the 587 blues   I used my HotSpot connection with T-Mobile yesterday. They were blocking port 587 but not 25. As I said, earlier ISP's blocking port 25 has so far not been a problem for us but YMMV. Having spammers targeting Imail directly is a much bigger problem in my book.   Jonas Fornander - System Administrator Netwood Communications,LLC - www.netwood.net Find out why we're better - 310-442-1530       From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dan Barker Sent: Wednesday, July 13, 2005 4:14 AM To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Solution to the 587 blues He'd need the original solution, a decent firewall. A firewall can route both 587 and 25 to 587, and as a side benefit, protect his network from the dark side of the 'net.   Dan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of John Tolmachoff (Lists) Sent: Wednesday, July 13, 2005 2:47 AM To: IMail_Forum@list.ipswitch.com Subject: RE: [IMail Forum] Solution to the 587 blues And in this configuration, how would you accommodate users on Internet Connections where their ISP has taken the step of blocking all outbound port 25 traffic?   John T eServices For You   -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jonas Fornander Sent: Tuesday, July 12, 2005 10:57 PM To: IMail_Forum@list.ipswitch.com Subject: [IMail Forum] Solution to the 587 blues   I found a solution to the problem of changing everyone to using port 587. I'm sure that most of you on this list have read the earlier messages and knows what I'm talking about. I also understand that this fix is not for everyone but I'm posting it here for those that eventually would be interested in other solutions than to change all their users to use port 587.   The only requirement is that you need to use a mail gateway such as IMGate. I have confirmed this workaround on my test box and with IMail tech that this works.   1. In Imail Administration go to SMTP -> Security and change the listening port for IMail from 25 to for example port 12345 2. In the registry go to HKEY_LOCAL_MACHINE/....../SMTP/Parameters and change the ExternalPort from the default 587 to 25. You must be using version 8.20 to be able to do this.   Viola!!!!! You now have an Imail server that is authenticating ALL incoming mail on port 25!   3. In your border router or firewall disable access to port 12345 (the port you changed Imail to listening on). 4. Change IMGate to relay mail to Imail on port 12345   This is what you have now: 1. All mail - spam or legit - using your MX record will send mail to IMGate on port 25 which will send it to Imail on port 12345 2. All your users will be able to send mail using mail.yourdomain.com on port 25 because they are authenticating. 3. All Sasser infected worm boxes on cable and DSL connections AND spammers targeting your IMail directly will be rejected because they can't authenticate.   And you don't have to change ANY mail configuration for any of your users as long as they typically use SMTP AUTH already.   Jonas Fornander - System Administrator Netwood Communications,LLC - www.netwood.net Find out why we're better - 310-442-1530   -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.8.13/47 - Release Date: 7/12/2005   -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.8.13/47 - Release Date: 7/12/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.8.13/47 - Release Date: 7/12/2005