Is IMSS an open relay mail server by default?

No, IMSS is not an open relay mail server by default. However, some administrative tools may incorrectly report that IMSS is an open relaymail server as IMSS allows some special characters such as the percent mark (%) and exclamatory mark (!) in email addresses. This causes some third-party administrative tools to misidentify IMSS as an open relay because some old UNIX mail server implementations treat such characters embedded in an email address as tricky source routings. You may do one of the following to prevent IMSS from being misidentified as an open relay mail server:

Apply the settings to all IMSS servers under one central database

If you have deployed IMSS in a distributed environment, run the following SQL statements to add new settings to the tb_mta_config table in the central database:
```
insert into tb_mta_config(section, name, value, inifile) 
values ( 'SmtpServer', ' RestrictInDomain', '1', 'tsmtpd.ini'); 
```
```
insert into tb_mta_config (section, name, value, inifile) 
values ( 'SmtpServer', ' RestrictInDomainMeta', ' !#$%', 'tsmtpd.ini');
```
Apply the settings to one IMSS server

Edit tsmtpd.ini (located in IMSS_INSTALL_ROOT\config\) and remove the comments for the following keys:

RestrictInDomain=1

RestrictInDomainMeta=!#$%

$('#title').html($('meta[name=description]').attr('content'));

Is IMSS an open relay mail server by default?