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Agreed, Assuming your mail server is set to receive email on TCP 587? If not you might want to use the following instead;<br />
<br />
access-list 101 extended permit tcp any host xxx.xxx.xxx.xxx eq 587<br />
static (inside,outside) tcp interface 587 xxx.xxx.xxx.xxx 25 netmask 255.255.255.255<br />
<br />
<br />
Regards,<br />
<br />
Pete
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<div>
Someone claims they are not seeing traffic sent on port 587, and has asked us to prove it is not an issue on our firewall. &nbsp;We are receiving traffic on port 587. &nbsp;<br />
<br />
Would there be additional steps after opening the port such as setting some kind of authentication or encryption in the firewall for port 587?
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<div>
Pete, <br />
Yes, it is set to receive mail on port 587.
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<div class="content wysiwyg-content">
Our ISP is requiring us to switch our SMTP traffic from port 25 to port 587. &nbsp;I wanted to permit this on my firewall, so I simply mimicked the configuration for port 25. &nbsp;Would this work? <br />
<br />
access-list 101 extended permit tcp any host xxx.xxx.xxx.xxx eq smtp <br />
static (inside,outside) tcp interface smtp xxx.xxx.xxx.xxx smtp netmask 255.255.255.255 <br />
<br />
access-list 101 extended permit tcp any host xxx.xxx.xxx.xxx eq 587<br />
static (inside,outside) tcp interface 587 xxx.xxx.xxx.xxx 587 netmask 255.255.255.255
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</div>


Our ISP is requiring us to switch our SMTP traffic from port 25 to port 587.  I wanted to permit this on my firewall, so I simply mimicked the configuration for port 25.  Would this work? 

access-list 101 extended permit tcp any host xxx.xxx.xxx.xxx eq smtp 
static (inside,outside) tcp interface smtp xxx.xxx.xxx.xxx smtp netmask 255.255.255.255 

access-list 101 extended permit tcp any host xxx.xxx.xxx.xxx eq 587
static (inside,outside) tcp interface 587 xxx.xxx.xxx.xxx 587 netmask 255.255.255.255

Configuring Port Access on Cisco ASA

Cisco PIX is a dedicated hardware firewall appliance; the Cisco Adaptive Security Appliance (ASA) is a firewall and anti-malware security appliance that provides unified threat management and protection the PIX does not. Other Cisco devices and systems include routers, switches, storage networking, wireless and the software and hardware for PIX Firewall Manager (PFM), PIX Device Manager (PDM) and Adaptive Security Device Manager (ASDM).