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Hello Experts, 
 
I am trying to publish an Exchange 2007 SMTP server listening on port 25 to the WEB behind two firewall zones and TMG. 
 
Security design is the following : 
[ WEB ] -- [ FW VLAN 6 ] -- [ TMG ] -- [ FW VLAN 10 ] -- [ EXCHANGE VLAN 1 ] 
 
On TMG, i have set 2 network interfaces : 
- VLAN06 with IP 172.22.6.3 as a perimeter interface 
- VLAN10 with IP 172.22.10.3 as an internal interface 
 
Some tests : 
- SMTP trafic is forwarded from public IP to VLAN06 to TMG (rule approved it and log trace) 
- Inbound trafic is received on TMG (log trace) 
- No trafic logged from TMG to Exchange 
- I am able to telnet Exchange on port 25 from TMG 
 
My problem : 
Running a telnet from outside to my pub address on port 25, i am not connected. 
 
I get an error : no rule seems to autorize my demand. 
Source : perimeter network with remote public address 
Destination : local host with VLAN06 address 
 
Rule is set to autorize SMTP from localhost / perimeter to Exchange 
 
Sometimes, I can get an WSAECONNREFUSED error without changing anything in the rule set. 
 
Any help would be great. 
Best regards,
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Hello Experts,

I am trying to publish an Exchange 2007 SMTP server listening on port 25 to the WEB behind two firewall zones and TMG.

Security design is the following :
[ WEB ] -- [ FW VLAN 6 ] -- [ TMG ] -- [ FW VLAN 10 ] -- [ EXCHANGE VLAN 1 ]

On TMG, i have set 2 network interfaces :
- VLAN06 with IP 172.22.6.3 as a perimeter interface
- VLAN10 with IP 172.22.10.3 as an internal interface

Some tests :
- SMTP trafic is forwarded from public IP to VLAN06 to TMG (rule approved it and log trace)
- Inbound trafic is received on TMG (log trace)
- No trafic logged from TMG to Exchange
- I am able to telnet Exchange on port 25 from TMG

My problem :
Running a telnet from outside to my pub address on port 25, i am not connected.

I get an error : no rule seems to autorize my demand. 
Source : perimeter network with remote public address
Destination : local host with VLAN06 address

Rule is set to autorize SMTP from localhost / perimeter to Exchange

Sometimes, I can get an WSAECONNREFUSED error without changing anything in the rule set.

Any help would be great.
Best regards,

Publish an SMTP server on TMG2010

Interactions between email servers and clients are governed by email protocols. The three most common email protocols are POP, IMAP and MAPI. Most email software operates under one of these (and many products support more than one).  The correct protocol must be selected, and correctly configured, if you want your email account to work.

Email Protocols

Microsoft Forefront, formerly known as Internet Security and Acceleration Server (ISA Server), is a network router, firewall, antivirus program, VPN server and web cache that runs on Windows servers. It includes identity management and protection systems, and discontinued systems for threat management and network protection, along with protection for Sharepoint and Exchange. The scope of discussions includes forward and reverse proxy, application and service publishing, virtual private networks (VPNs), outbound access rules, SSL certificates and network routing within either a single node or an highly-available array pairing.

Microsoft Forefront ISA Server

Anti-virus software was originally developed to detect and remove computer viruses. However, with the proliferation of other kinds of malware, antivirus software started to provide protection from other computer threats. In particular, modern antivirus software can protect from malicious browser helper objects (BHOs), browser hijackers, ransomware, keyloggers, backdoors, rootkits, trojan horses, worms, malicious layered service providers (LSPs), dialers, fraud tools, adware and spyware. Some products also include protection from other computer threats, such as infected and malicious URLs, spam, scam and phishing attacks, online identity theft (privacy), online banking attacks, social engineering techniques, Advanced Persistent Threat (APT), botnets and DDoS attacks.