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Linux Resources

Secure Connections

Your Linux distribution should have OpenSSH prepackaged and, quite likely, already installed. This should make ssh and scp availabe on the command line. You may also want to check rsync, which is a command line utility to copy or synchronize entire directory trees, while transferring only the difference in file contents.

Filezilla is a GUI program for both SSH File Transfer or SFTP. Install using your distribution's software manager or download from filezilla-project.org. Lauch the program, choose File > Site Manager > New Site. Configure SFTP connection to gauss:

Host: math.dartmouth.edu
Servertype: SFTP - SSH File Transfer Protocol
Logontype: Ask for password
User: your username on gauss

Click OK to save configuration or Connect to save and connect at once.

VPN

Dartmouth VPN

In 2009 Dartmouth switched to Juniper VPN. It works fine on 32-bit Linux. It does not work on 64-bit systems (Sep. 2012). Dartmouth VPN can be started at gateway.dartmouth.edu. It uses web browser's Java applet to download and run VPN client. (Test your browser's Java here.)

Math VPN

Math VPN uses OpenVPN technology.

  1. Install OpenVPN and Network Manager's component for OpenVPN.
    (openvpn, network-manager-openvpn packages in Debian/Ubuntu).
  2. Download DigiCert root certificate.
  3. Add Math VPN connection in Network Manager:
    1. VPN Connections → Configure VPN.
    2. Add → OpenVPN → Create....
    3. Connection name: Math VPN.
    4. Gateway: 129.170.28.37.
    5. Authentication Type: Password.
    6. User name: your Math username
    7. Password: choose Always Ask
    8. CA Certificate: point to downloaded DigiCert certificate
    9. Apply.
  4. To connect click on Network Manager's applet, VPN Connections → Math VPN.
  5. To disconnect use Disconnect VPN in the same applet.

Math Email (and the DND)

If you have Math Dept. user account (also known as “gauss” account), you also have a corresponding email account. Your Math email arrives at (and can be sent from) math.dartmouth.edu server. It can be accessed instantly and globally via Webmail — this does not require any configuration! As for email applications, all of them, including mobile, can be configured to use your Math account using these generic settings:

  • Mail server type: IMAP
  • Incoming server: math.dartmouth.edu, port: 143
  • Connection type/encryption: TLS
  • Username: your Math username
  • Password: for the username above
  • Outgoing/SMTP server: math.dartmouth.edu, port: 25

Darmouth Name Directory lookups in Thunderbird

Edit → Preferences → Composition → Addressing
Click Edit Directories, Add:

General tab:
Name: Dartmouth Directory
Hostname: ldap.dartmouth.edu
Base DN: dc=dartmouth, dc=edu
Port number: 389
Back in the Preferences window select “Dartmouth Directory” for Directory Server.

Vacation Autoreply

Autoreply message text for your Math mail is in .vacation.msg in your home directory on gauss.

Autoreply is enabled by uncommenting the following two lines in .procmailrc:

#:0c
#|/usr/bin/vacation username
To stop autoreply, comment both lines out again, by inserting # as the first character on each line.

.vacation.msg and .procmailrc can be edited with any text editor while on gauss terminal or with a variety of GUI tools from Linux desktop, for example, Filezilla, Nautilus, Dolphin etc.

Backups

Your workstation can be backed up to Math Dept. network storage. Contact help@math.dartmouth.edu for assistance.

Printing

Math Dept. network printers are used via printing service CUPS running on gauss. With CUPS browsing enabled all Math printers should be automatically available, if your Linux machine is connected to Kemeny Hall wired network. Drivers are already installed on print server — there is no need for individual printer configuration on a client.

CUPS browsing can be enabled by from http://localhost:631:
Administration: Server Settings: enable Show printers shared by other systems.

Similar setting is likely available in system preferences/settings menu in Gnome, KDE, XFCE etc.

Alternatively, CUPS browsing can be enabled by editing /etc/cups/cupsd.conf and setting: 

    Browsing on
To limit the list of available printers to those served by gauss (i.e. Math printers only) set 
    BrowseAllow 129.170.28.37
To access Math printers from Dartmouth Secure Wi-Fi add 
    BrowsePoll 129.170.28.37
Restart CUPS for changes to take effect: 'service cups restart'.
Check for available printers: 'lpstat -t'.

Condor Installation

  1. Add system user “condor”: 
    adduser --disabled-login --shell /bin/false condor
  2. Download Condor package from www.cs.wisc.edu and put it into /usr/local/.
  3. Unpack, install: 
    cd /usr/local
tar vxzf condor-version.tar.gz
ln -s /usr/local/condor-version /usr/local/condor
./condor_configure --install --type=submit --owner=condor \
    --central-manager=math-01.grid.dartmouth.edu
mkdir /etc/condor
ln -s /usr/local/condor/etc/condor_config /etc/condor/condor_config
  4. Adjust local configuration file /usr/local/condor/local.hostname/condor_config.local by adding: 
    FILESYSTEM_DOMAIN = $(FULL_HOSTNAME)
UID_DOMAIN = $(FULL_HOSTNAME)
ALLOW_WRITE=*.dartmouth.edu, 127.*
ALLOW_READ=*.dartmouth.edu, 127.*
RESERVED_SWAP = 0
  5. Copy start/stop script to /etc/init.d/: 
    cp /usr/local/condor/etc/examples/condor.boot /etc/init.d/condor
  6. Start Condor: 
    /etc/init.d/condor start
  7. Check communication with the pool: 
    /usr/local/condor/bin/condor_status
    The response should be similar to this: 
    Name               OpSys  Arch   State     Activity LoadAv Mem   ActvtyTime
slot1@math-01.grid LINUX  X86_64 Unclaimed Idle     0.020  1024  0+03:25:04
slot2@math-01.grid LINUX  X86_64 Unclaimed Idle     0.000  1024  5+23:27:12
slot1@math-02.grid LINUX  X86_64 Unclaimed Idle     0.000  1024  0+03:05:04
slot2@math-02.grid LINUX  X86_64 Unclaimed Idle     0.000  1024  6+00:41:04
slot1@math-03.grid LINUX  X86_64 Unclaimed Idle     0.000  1024  1+03:05:24
slot2@math-03.grid LINUX  X86_64 Unclaimed Idle     0.030  1024  0+03:05:05
... ... ...
    Condor log files are in /usr/local/condor/local.hostname/log/.
  8. If firewall is in use, configure Condor to use port range of 9600-9700 and then open firewall for incoming and outgoing TCP and UDP in that port range. Add to condor_config.local: 
    LOWPORT = 9600
HIGHPORT = 9700
    iptables rules may look like this: 
    iptables -A INPUT -s 129.170.0.0/16 -p tcp -m state --state NEW --dport 9600:9700 -j ACCEPT
iptables -A INPUT -s 129.170.0.0/16 -p udp -m state --state NEW --dport 9600:9700 -j ACCEPT

Joining Condor pool as an “execute” node

Instructions above are for configuring Condor as a submit-only node. With only minor changes in configuration this can be changed into submit and execute node. Please consider adding your workstation as an execute node, especially if it's a fairly new machine. In your local configuration file condor_config.local replace the line 

DAEMON_LIST = MASTER, SCHEDD
with 
DAEMON_LIST = MASTER, SCHEDD, STARTD
Restart Condor. After a few moments your workstation should appear in condor_status listing. If you have Mathematica, Maple, Matlab or GP/PARI installed, add the following lines to condor_config.local: 
HAS_MATH = TRUE
HAS_MAPLE = TRUE
HAS_MATLAB = TRUE
HAS_GP = TRUE
STARTD_EXPRS = HAS_MATH HAS_MAPLE HAS_MATLAB HAS_GP

Dartmouth PKI Certificates

Accessing certain resources on Dartmouth network may require digital certificates.
Two certificates are involved:

  1. Dartmouth Certificate Authority's root certificate.
  2. Your personal Dartmouth certificate.
Both can be obtained by navigating to collegeca.dartmouth.edu. Certificates will appear in your web browser's certificate store. For Firefox it is in Preferences → Advanced → Encryption → View Certificates. Dartmouth root certificate should be listed under Authorities; your personal — under Your Certificates.

Certificates can be exported as disk files from View Certificates → Your Certificates. Select your personal certificate and click Backup to save it in PKCS12 file (extension .p12). You will be asked to create “Certificate backup password”. In addition to your personal certificate the PKCS12 file will also contain your private key and the Dartmouth CA root certificate.

(Optional) Convert from PKCS12 to PEM

PKCS12 file contains Dartmouth CA cert., your personal cert. and your private key in one compound format. In some cases certificates/keys have to be presented as separate files. Use OpenSSL commands below to convert PKCS12 to individual PEM files.

CA's root certificate: 

    openssl pkcs12 -in mydccert.p12 -cacerts -nokeys -out collegeca.pem

Personal certificate: 

    openssl pkcs12 -in mydccert.p12 -clcerts -nokeys -out mydccert.pem

Private key: 

    openssl pkcs12 -in mydccert.p12 -clcerts -nocerts [-nodes] -out mydckey.pem

As a result, collegeca.pem will contain Dartmouth CA's root certificate, mydccert.pem — your personal Dartmouth certificate, mydckey.pem — private key, associated with your personal certificate. Optionally -nodes will output your private key unencrypted, i.e. not protected by a password — please make sure, that it's kept securely!.

Connecting to Dartmouth Secure Wireless Network

Use the following settings with your NetID and password:

Wireless Security:
Security: WPA & WPA2 Enterprise
Authentication: Protected EAP (PEAP)
Inner auth. (EAP method): MSCHAPv2
Username: your NetID

Settings in Network Manager applet