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Working with a Cisco 1841 router, I want to lock down email to come from only Postini. 
I see many solutions for PIX firewalls, but not just routers. 
Postini is at 64.18.0.0/20 &nbsp;or 64.18.0.0 255.255.240.0 &nbsp;or 64.18.0.0 through 64.18.15.255 
This router also handles a voip channel on a different subnet and physical port 
 
What is working now - before locking it down: 
ip access-list extended serial0/0/0 
&nbsp; permit tcp any host x.x.x.41 eq 3389 
&nbsp; permit tcp any host x.x.x..42 eq 3389 
&nbsp; permit tcp any host x.x.x.43 eq 3389 
&nbsp; permit tcp any host x.x.x.42 eq smtp 
&nbsp; deny ip host 255.255.25.255 any 
&nbsp; deny ip host 0.0.0.0. any 
 
I have removed the permit.... smtp with a NO 
 
I have tried to add: 
&nbsp; permit tcp 64.18.0.0 255.255.240.0 host x.x.x.42 eq smtp 
 
What I get in response is: 
&nbsp; permit tcp 0.0.0.0 255.255.240.0 host x.x.x.42 eq smtp 
 
help please - my syntax must be in error... 

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Working with a Cisco 1841 router, I want to lock down email to come from only Postini.
I see many solutions for PIX firewalls, but not just routers.
Postini is at 64.18.0.0/20  or 64.18.0.0 255.255.240.0  or 64.18.0.0 through 64.18.15.255
This router also handles a voip channel on a different subnet and physical port

What is working now - before locking it down:
ip access-list extended serial0/0/0
  permit tcp any host x.x.x.41 eq 3389
  permit tcp any host x.x.x..42 eq 3389
  permit tcp any host x.x.x.43 eq 3389
  permit tcp any host x.x.x.42 eq smtp
  deny ip host 255.255.25.255 any
  deny ip host 0.0.0.0. any

I have removed the permit.... smtp with a NO

I have tried to add:
  permit tcp 64.18.0.0 255.255.240.0 host x.x.x.42 eq smtp

What I get in response is:
  permit tcp 0.0.0.0 255.255.240.0 host x.x.x.42 eq smtp

help please - my syntax must be in error...


Lock down 1841 Router to Postini SMTP only

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.

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Network Operations includes asset management, help-desk supervision, security and user policies, infrastructure administration and anything else that affects the operation of your network. Discussions will include those of best practices in platforms, configurations, performance, security and accounting.