https://community.cisco.com/t5/network-security/nat-question-why-does-this-not-work/m-p/3683152#M13028 <P>Hi,</P> <P>&nbsp;</P> <P>I have the following NAT rule for an internal server to reach an SMTP server:</P> <P><STRONG><FONT face="courier new,courier">nat (inside,outside) dynamic interface</FONT></STRONG></P> <P>&nbsp;</P> <P>If I change the above to the nat rule below, email is not sent:</P> <P><STRONG><FONT face="courier new,courier">nat (inside,outside) static interface service tcp smtp smtp&nbsp;</FONT></STRONG></P> <P>&nbsp;</P> <P>Why would&nbsp;the second rule not work? Is it not doing the same thing (including also&nbsp;allowing a bi-directional connection)?</P> Fri, 21 Feb 2020 16:04:02 GMT Cizco 2020-02-21T16:04:02Z https://community.cisco.com/t5/network-security/nat-question-why-does-this-not-work/m-p/3683152#M13028 <P>Hi,</P> <P>&nbsp;</P> <P>I have the following NAT rule for an internal server to reach an SMTP server:</P> <P><STRONG><FONT face="courier new,courier">nat (inside,outside) dynamic interface</FONT></STRONG></P> <P>&nbsp;</P> <P>If I change the above to the nat rule below, email is not sent:</P> <P><STRONG><FONT face="courier new,courier">nat (inside,outside) static interface service tcp smtp smtp&nbsp;</FONT></STRONG></P> <P>&nbsp;</P> <P>Why would&nbsp;the second rule not work? Is it not doing the same thing (including also&nbsp;allowing a bi-directional connection)?</P> Fri, 21 Feb 2020 16:04:02 GMT https://community.cisco.com/t5/network-security/nat-question-why-does-this-not-work/m-p/3683152#M13028 Cizco 2020-02-21T16:04:02Z https://community.cisco.com/t5/network-security/nat-question-why-does-this-not-work/m-p/3683797#M13032 run packet trace and see what is happening with 2nd rule.<BR /> Wed, 08 Aug 2018 02:52:41 GMT https://community.cisco.com/t5/network-security/nat-question-why-does-this-not-work/m-p/3683797#M13032 Mohammed al Baqari 2018-08-08T02:52:41Z