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There's been countless times when I've needed to test for SMTP user enumeration (RCPT TO and VRFY), internal spoofing, and open relay. I've never found a tool that tested for all three and with great flexibility. iSMTP does just that, making it much easier to knock that process out of the way.


Usage menu:

[07.22.2017/21:34:09] root@box $ ./

  SMTP v1.6 - SMTP Server Tester, Alton Johnson (
 Usage: ./ <OPTIONS>


   -f <import file>  Imports a list of SMTP servers for testing.
                     (Cannot use with '-h'.)
   -h <host>         The target IP and port (IP:port).
                     (Cannot use with '-f'.)


   -i <consultant email>   The consultant's email address.
   -s <sndr email>         The sender's email address.
   -r <rcpt email>         The recipient's email address.
      --sr <email>         Specifies both the sender's and recipient's email address.
   -S <sndr name>          The sender's first and last name.
   -R <rcpt name>          The recipient's first and last name.
      --SR <name>          Specifies both the sender's and recipient's first and last name.
   -m                      Enables SMTP spoof testing.
   -a                      Includes .txt attachment with spoofed email.

 SMTP enumeration:

   -e <file>   Enable SMTP user enumeration testing and imports email list.
   -l <1|2|3>  Specifies enumeration type (1 = VRFY, 2 = RCPT TO, 3 = all).
               (Default is 3.) 

 SMTP relay:

   -i <consultant email>   The consultant's email address.
   -x                      Enables SMTP external relay testing.


   -t <secs>   The timeout value. (Default is 10.)
   -o          Creates "ismtp-results" directory and writes output to

 Note: Any combination of options is supported (e.g., enumeration, relay, both, all, etc.).
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