exim: rejected EHLO, syntactically invalid argument
If you email having problem with rejected EHLO or HELO, caused by syntactically invalid argument(s).
- Possible the hostname contains underscore(_).
- This is not standard practice, having _ for your domain
- for example takizo_mail.takizo.com
- Most of the mail server rejected hostname with underscore.
- Possibility is a Windows Admin
Error message shows in exim’s log;
2007-01-31 09:13:21 rejected EHLO from [18.104.22.168]: syntactically invalid argument(s): stupid_proxy.windowsadmin.com.my
2007-01-31 09:13:21 rejected HELO from [22.214.171.124]: syntactically invalid argument(s): stupid_proxy.windowsadmin.com.my
Solutions: Add this line in exim configuration main section;
helo_allow_chars = _
Now your exim should be working and receive email from the l33t! hostname. _hell_.lamer.com