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Can you telnet from the Exchange Server to port 25 on the smart host that you are using to forward mail? &nbsp;The default on ISA is to allow all internal clients open access to external sites and services. &nbsp;You may be having a reverse lookup problem. &nbsp;Are you using the ISA firewall client or a secure NAT configuration?
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Can you telnet from the Exchange Server to port 25 on the smart host that you are using to forward mail?  The default on ISA is to allow all internal clients open access to external sites and services.  You may be having a reverse lookup problem.  Are you using the ISA firewall client or a secure NAT configuration?

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Since the answer is the same for ISA Server as for the (old) MS Proxy 2.0, the URL is always the same:<br />
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<a href="http://proxyfaq.networkgods.com" rel="ugc">http://proxyfaq.networkgods.com</a><br />
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have fun<br />

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Since the answer is the same for ISA Server as for the (old) MS Proxy 2.0, the URL is always the same:

http://proxyfaq.networkgods.com [http://proxyfaq.networkgods.com]

have fun


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I have an ISA server with two NIC's one external one internal, the latter passes internet requests to the other and visa versa, no rocket science there. My problem is that my Exchange 5.5 server does not send/recieve mail from withinside the firewall, and I,m sure it is an ISA protocol rule, or something simple like that, I am having difficulty finding any information &nbsp;with regards protocols/rules than need to be enabled. My exchange server sends and recieves using &quot;Message Delivery&quot; type &quot;Forward all messages to host&quot;.<br />
Any pointers or ideas would be much appreciated.
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I have an ISA server with two NIC's one external one internal, the latter passes internet requests to the other and visa versa, no rocket science there. My problem is that my Exchange 5.5 server does not send/recieve mail from withinside the firewall, and I,m sure it is an ISA protocol rule, or something simple like that, I am having difficulty finding any information  with regards protocols/rules than need to be enabled. My exchange server sends and recieves using "Message Delivery" type "Forward all messages to host".
Any pointers or ideas would be much appreciated.

Configure Exchange 5.5 inside an ISA firewall

Software firewalls, also known as host-based firewalls, provide a layer of software on one host that controls network traffic in and out of that single machine. Most operating systems now include firewall software, but many available software firewalls include central distribution, antivirus systems and disaster recovery.

Software Firewalls

Security is the protection of information systems from theft or damage to the hardware, the software, and the information on them, as well as from disruption or misdirection of the services they provide. The main goal of security is protecting assets, and an asset is anything of value and worthy of protection.  Information Security is a discipline of protecting information assets from threats through safeguards to achieve the objectives of confidentiality, integrity, and availability or CIA for short. On the other hand, disclosure, alteration, and disruption (DAD) compromise the security objectives.