$ telnet <a href="http://smtp.san.ru">smtp.san.ru</a> 25<br>Trying 88.147.128.28...<br>Connected to <a href="http://smtp.san.ru">smtp.san.ru</a> (88.147.128.28).<br>Escape character is '^]'.<br>220 PREVED!!!<br>preved<br>
501 Unknown command<br>quit<br>221 <a href="http://san.ru">san.ru</a> PAKA!<br>Connection closed by foreign host.<br><br>