error messages

[=?ISO-8859-1?Q?Kaj_M=E4kinen?=]

I  connect to my firewall with putty. How can I get rid of messages like 
these from
appearing in my ssh terminal session? These appeared twice a second so 
it is wery hard to
work with the console.
(It was obviously someone trying to  get access to something?)

May 16 18:30:05 localhost sshd[21201]: Failed password for root from 
64.42.53.150 port 48385 ssh2
May 16 18:30:06 localhost sshd[21201]: Received disconnect from 
64.42.53.150: 11: Bye Bye
May 16 18:30:08 localhost sshd[12553]: Failed password for root from 
64.42.53.150 port 48446 ssh2
May 16 18:30:08 localhost sshd[12553]: Received disconnect from 
64.42.53.150: 11: Bye Bye
May 16 18:30:11 localhost sshd[23351]: Failed password for root from 
64.42.53.150 port 48543 ssh2
May 16 18:30:11 localhost sshd[23351]: Received disconnect from 
64.42.53.150: 11: Bye Bye
May 16 18:30:14 localhost sshd[13243]: Failed password for root from 
64.42.53.150 port 48628 ssh2