IP Networking Software Configuration

Suitably equipped personal computers can be connected to JANET and the Internet via the Cambridge University Data Network (CUDN). Connections may be made via a Local Area Network (LAN - usually ethernet), the Lapwing wireless service or eduroam, or the VPDN (Virtual Private Dialup Network) service.

Any computer system that is connected to the Internet should be considered as vulnerable to external attack. For further information and advice please refer to IS28 Security implications of attaching a computer to a College or Departmental network.

TCP/IP configuration

The underlying TCP/IP software must be installed on each machine (if necessary) and correctly configured for use within the cam.ac.uk domain. The rest of the information in this first section applies to computers connected via a LAN. Users of Lapwing, eduroam or the VPDN service are allocated a temporary IP address each time they connect and do not need to request one. For further details on using the VPDN see remote access For further details on wireless connection see Wireless networking.

IP addresses should normally be requested from your local support staff (College or Departmental Computer Officer). Please refer to the page on IP Addresses for further details.

Information for Computer Officers about IP address space management is also available online.

When you receive your IP address you will also receive information about:

• Gateway router IP address
• Net mask
• Local DNS (Domain Name Server) if known

The primary Computing Service DNS name servers are:
recdns0.csx.cam.ac.uk (131.111.8.42) and recdns1.csx.cam.ac.uk (131.111.12.20)

If you have a client that can point to only one server, use recdns0.csx.cam.ac.uk (131.111.8.42). If there is a local DNS available, then use this in preference to the Computing Service nameservers.

Information for Computer Officers about IP address space management is at IP address management for Institutional Computer Officers

Private addresses

If, when you get your IP address, the corresponding name ends .private.cam.ac.uk, your computer can only directly contact other machines in Cambridge (names ending .cam.ac.uk). The Computing Service runs a NAT (Network Address Translation) service that enables these systems to have access to the Internet and some Institutions also run a suitable gateway or proxy device. Please see your local Computer Support staff if there are problems.

Email

The main Computing Service mail store is Hermes. Hermes is accessible through the Webmail interface or you can use a mail client.

Mail client programs (MUAs) must be configured to use secure settings. See the email web pages for further information. In particular, see Email program settings for Hermes for information on configuring mail clients, including how to configure SMTP AUTH. Configuring this will allow you to use Hermes to send mail using your usual mail client when you are away from Cambridge. It also allows visitors to Cambridge who need to send mail from their usual address to do so using the Hermes SMTP server, authenticating with their Cambridge username (CRSid) and password. Wherever possible you are encouraged to configure mail clients to use IMAP to read mail, especially if you access your mail from more than one system. POP is only suited to those who use a single computer and is not recommended for those who wish to access their email from more than one system as messages are downloaded to the client system and deleted from the server.

World Wide Web

Web browsers may be configured to point to the University home page (http://www.cam.ac.uk/) or, if available, to a local home page.

Network Time

Network Time Protocol (NTP) keeps a computer clock synchronized to the correct time. The Computing Service supports an NTP service. Computer Officers who are interested in providing this facility within their institution should contact timelord@ucs.cam.ac.uk in the first instance.

If there is an NTP server in your department or College then use this in preference to the Computing Service servers. Otherwise select one of ntp0.csx.cam.ac.uk, ntp1.csx.cam.ac.uk, or ntp2.csx.cam.ac.uk. For most systems checking the time once every 24 hours will be sufficient.

Remote Access

The Computing Service provides remote login access via SSH (secure shell) to Hermes, the host login name is hermes.cam.ac.uk

Remote login access to the MCS is available via SSH to the Linux service at linux.pwf.cam.ac.uk, allowing access to the DS-Filestore filespace and to the applications offered by MCS Linux. Access to your DS-Filestore filespace is also available by several other means. There is no remote access at present to the MCS Windows or Macintosh applications.

Macintosh and Windows PC users may need to install an application capable of making secure connections e.g. JellyfiSSH for Mac OS X, or use ssh from the Terminal or iTerm; PuTTY for PCs running Windows.

SFTP and FTP file transfer

The Computing Service provides SFTP (Secure FTP) and SCP (Secure copy) access to the Hermes filestore, and to users' files on the MCS.

Hermes note: access is to the Hermes filestore only. This does not give access to mail folders; access to these is through a mail program or the Webmail interface.

A local anonymous ftp server for Cambridge-only access is at ftp.csx.cam.ac.uk

The University of Kent runs a Mirror Service which provides a collection of mirrors of FTP, web and rsync sites of interest to academic users.

Further information on FTP, SFTP and SCP is available.

Further Information

A range of leaflets are available online.

Further information on computer security is also available.

For information about ethernet (or other) connections to your Local Area Network, please refer to your local Computing Support Staff.

Last updated: October 2011