Passwords that are random enough to resist dictionary attacks are quite difficult to create, and even harder to remember. Personally, I think writing down your password, while suboptimal, is far superior to using a weak password. Bruce Schneier reccomends that you write down your password
personally, I think that even if you leave the (strong) password on a post-it on your monitor (please don't do that) it's still safer than using a weak password. Nobody in China can see the post-it, but anyone in the world can try passwords against your server.
The possibility of a dictionary attact is not an idle threat; see below for evidence from my servers.
this is just a small snippet of a logfile from my mailserver:
Feb 3 09:39:14 luke sshd[4004]: input_userauth_request: invalid user tester Feb 3 09:39:14 luke sshd[4002]: pam_unix(sshd:auth): check pass; user unknown Feb 3 09:39:14 luke sshd[4002]: pam_unix(sshd:auth): authentication failure; lo gname= uid=0 euid=0 tty=ssh ruser= rhost=raq121.servercity.co.uk Feb 3 09:39:16 luke sshd[4003]: Failed password for invalid user admin from 217 .205.136.63 port 35143 ssh2 Feb 3 09:39:16 luke sshd[4002]: Failed password for invalid user tester from 21 7.205.136.63 port 35142 ssh2 Feb 3 09:39:17 luke sshd[4005]: Received disconnect from 217.205.136.63: 11: By e Bye Feb 3 09:39:17 luke sshd[4004]: Received disconnect from 217.205.136.63: 11: By e Bye Feb 3 09:39:18 luke sshd[4007]: Invalid user tester from 217.205.136.63 Feb 3 09:39:18 luke sshd[4008]: input_userauth_request: invalid user tester Feb 3 09:39:18 luke sshd[4007]: pam_unix(sshd:auth): check pass; user unknown Feb 3 09:39:18 luke sshd[4007]: pam_unix(sshd:auth): authentication failure; lo gname= uid=0 euid=0 tty=ssh ruser= rhost=raq121.servercity.co.uk Feb 3 09:39:18 luke sshd[4006]: Invalid user admin from 217.205.136.63 Feb 3 09:39:18 luke sshd[4009]: input_userauth_request: invalid user adminthis file, which was rotated several days ago:
[lsc@luke ~]$ sudo wc -l /var/log/secure 261677 /var/log/secure
devide that by 4 or 5 to get the number ot attemted logins... but that's still a lot I've checked a few other public servers I have access to, and this is not unusual. Use Strong Passwords.
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