FreeBSD Blog

Change FTP Port

December 31, 2005 Posted in Security

After I changed the ssh port, combined with the changes of net.inet.tcp.blackhole and net.inet.udp.blackhole, now the server is completely free of ssh login attempts. I realized these two changes should be made together, it doesn’t make much sense to change only one of them. For example, if only change the port, the server will still respond to the port scan, it very probably gets more scan activity. What if only changed the system varibles? Since the ports of common services are the main target, the evil people still can easily find the ports to attack. Read More

Change sshd Port

December 26, 2005 Posted in Security

I used default port number 22 for sshd, the server got lots of login attempts every day which left thousands of lines in daily security run output. Read More

Postfix Mail Queue

December 11, 2005 Posted in Email

List the mail queue:
# /usr/bin/mailq

Delete a mail by mail id (get the mail id with the above command):
# postsuper -d mail_id

Delete all message in the mail queue:
# postsuper -d ALL

Flush the queue: attempt to deliver all queued mail:
# postqueue -f