scadblog

I forgot how to SSH without a password today, so that requires that I make an entry here so I will remember for all time (apparently I’ve given up on my brain’s ability to retain information).

On your local machine:

ssh-keygen -d

Enter a passphrase if you wish to lock the private key forever-more. If you enter a passphrase, be prepared to be prompted for that instead of your password. You will be prompted for the passphrase each time you attempt to use the key (more on that later).

Once you have the private and public keys generated, copy your public key to the remote host you wish to connect to like so:

scp .ssh/id_dsa.pub username@remotehost:.ssh/authorized_keys

Then you’re ready to go. Just ssh username@remotehost and you should not be asked for a password. If you set a passphrase though you will be asked for that each time. To avoid re-entering the passphrase each time, run:

ssh-agent

in your terminal. This program manages your keys and passphrases. You add your key to it by typing:

ssh-add

It will then ask you for your passphrase. This will be the only time you need enter it for that session, thus the advantage of using ssh-agent and adding your key to it. Of course, all of that is in no way necessary if you didn’t add a passphrase to your private key to begin with.

[addendum]

related howto article

Nifty little trick to identify your Red Hat distro:

cat /etc/redhat-release

Retail outlets are hardly my first choice for supplies. Even so, I found myself at CompUSA yesterday to pick up a few disks. When I brought all of the items to the counter and proudly displayed my departmental credit card and tax exemption form, I was flatly denied service. The two drones behind the cashier’s counter claimed that if my name was not on the credit card, I could not purchase the items in question. Mind you, I have shopped the Comp more than once in the past, with no trouble about the card, especially since there’s a big “Purchasing Card” logo plastered across the front.

I did that frustrated customer stare at the cashiers for all of two seconds. I explained my situation to them and a brief summary of my history shopping there. Seconds away from talking to the manager, I realized I was pressed for time and had a few more stops to make. So I resigned to getting what I needed over at Best Buy where they were more than happy to greet me as “Susan” and rush me out the door. So beware CompUSA if you’re short on time and don’t want to wait around for the staff to figure out what a purchasing card is for just so you can pick up a few supplies.

When using fdisk to create a partition table, don’t fret if you get a warning message stating that “partition n has an empty type”. Just take a deep breath, restart your partitioning from scratch and instead of typing ‘a’ for add new partition, type ‘n’ for new partition.

*slaps forehead*

This project looks really interesting, especially because I don’t have a licensed solution for file archive creation in either department. Free is certainly worth checking out. The interface is a little counter-intuitive but its not the worst I’ve seen. 7-zip will create and unpack zip, arj, tar, rar, cab and deb among other formats, all on your Windows desktop.

Hey, where are all my gifts? Its System Administrator Day!

I hope someplace, sometime on campus this tidbit saves someone a Friday headache. I would have really liked to have remember this earlier today. I was freaking out all day over the fact that my machine had just stopped packet forwarding out of the blue.

Only now do I remember that I didn’t script the following command at startup, and that my machine underwent a reboot earlier in the week. So ladies and gentlemen, if you’re going to packet forward, do yourself a favor and throw this little switch before throwing the computer out the window.

From the command line: echo 1 > /proc/sys/net/ipv4/ip_forward

Or change net.ipv4.ip_forward = 0 to net.ipv4.ip_forward = 1 in /etc/sysctl.conf to have the setting last through a reboot.