ssh tunnelling command-line

The commandline for ssh tunnelling, taken from http://www.brandonhutchinson.com/ssh_tunnelling.html

ssh -f -N -L 1234:localhost:80 user@Remote_Machine

for web-server.

SHA1 sum check

Just like the MD5 checksum, SHA1 checksum can be done with

sha1sum filename

Used with Fedora iso downloads, for example.

combating spam from feedback forms

One more technique to supplement the one I've described earlier - check for the string http:// and don't email the form if present! In asp, that translates to

if Instr(strString,"http://") then
Response.Write " -- "
else
Mail.Send 
end if