IP Host Name Registration


Table of Contents


Introduction


Each network device on the campus network must have a unique IP address before it can connect with Internet services. This is true for the current UCDNet as well as for the new Network 21 infrastructure.

After you have received your Network 21 IP address allocation, you will assign a unique IP address to each network device in your area. In addition, it is recommended that you register an IP host name for each network device.

If possible, send your host name registration request 2 weeks prior to your actual cutover date.


Reasons for Host Name Registration


Internet Servers:
Host name registration is essential for Internet servers in your department. If your department has a Web server in your department, people connect to the server with a URL that includes its host name (e.g., http://net21.ucdavis.edu/, where 'net21.ucdavis.edu' is the host name).

Reverse IP Lookup:
Some Internet sites do a reverse lookup on your IP address when you try to connect. If your workstation does not have a registered host name, you will not be allowed to connect. For example, the I.T. software distribution servers rely on reverse lookup -- you can copy software for free, but you must connect from a computer with a UC Davis registered host name. If your workstation does not have a registered host name, you may get an error message that says something like 'No permission' or 'Reverse lookup failed' when you try to connect with Web pages, News servers and FTP sites.

Convenience:
It is easier to refer to computers in the office by a host name than by 'that computer over there'.

The Host Name Clerk


The host name table for most network devices on UCDNet is maintained by the campus Host Name Clerk. The Host Name Clerk is a live person who takes your requests and enters them in a central host name table that will include entries for the current UCDNet as well as the new Network 21 infrastructure.


Converting Your Registered Host Names


Host name registration is nothing new. Network devices in your area may already have registered host names.

You can request a list of the currently registered host names on your UCDNet subnet by sending an e-mail message to hostclerk@ucdavis.edu. Include your current IP address range and your Employee ID number. The Host Name Clerk will return a list of the host names that are registered for those IP addresses. Note: If you are uncomfortable giving your Employee ID in an e-mail message, please give your full name instead.

Since a host name is registered to a unique IP address, and since the IP address of a network device will change when it is cut over to the Network 21 infrastructure, you must inform the Host Name Clerk of the new IP address for each network device in your area that will be cut over to the Network 21 infrastructure.

You may choose to retain your current host names, or select new ones as you cut over to the Network 21 infrastructure.

For instructions on retaining your current host names or requesting new ones, see How to Register Host Names for the Network 21 Infrastructure.


You May Retain Current Host Names or Select New Ones


If you already have registered host names for your network devices they are reserved for you on the Network 21 infrastructure. Follow the instructions found at, How to Register Host Names for the Network 21 Infrastructure, to convert the host name registration from the current IP address to the new Network 21 IP address.

Note: You can retain only those host names already assigned to IP addresses in your area. You cannot use host names registered to other departments.

If you are dissatisfied with the host names that are currently registered for your network devices, you may select new host names. For more information, see How to Dream Up a Host Name. Note: I.T. does not assign host names; host name registration has always been at the discretion of the department network administrator.

If you don't yet have registered host names for your network devices, you may select host names now. For more information, see How to Dream Up a Host Name.


Timing Considerations


In general, it is best to convert your host names on the day your network devices are cut over to the Network 21 infrastructure.

Ideally, your host name registration conversion will occur during your cutover downtime window. In the ideal case, you'll prepare for the host name conversion prior to your cutover date; the host name conversion processing will occur at the same time your network is down for cut over; your new host name registrations will be ready when your computers come back on-line on the new Network 21 infrastructure.

Timing is especially important when it comes to your department's Internet servers ( e.g., Web server ). If the host name re-registration for your network server does not coincide with the Network 21 IP address cutover, people will be unable to connect to your server by its host name.

The next section explains how to stage your host name registration requests so that re-registration occurs on the same date as your Network 21 cutover.


How to Register Host Names for Network 21


Summary of Net21 Host Name Registration Process

Obtain List of Existing Host Names, If Needed

You can request a list of the currently registered host names on your UCDNet subnet by sending an e-mail message to hostclerk@ucdavis.edu. Include your current IP address range and your Employee ID number. The Host Name Clerk will return a list of the host names that are registered for those IP addresses. Note: If you are uncomfortable giving your Employee ID in an e-mail message, please give your full name instead.

Receive Net21 IP Address Range and Cutover Date

You should receive your Net21 IP address range assignment and your scheduled Net21 cutover date about one month prior to the actual cutover date.

Note: IP addresses for the Network 21 infrastructure will begin with 169.237. Most IP addresses on the current UCDNet infrastructure begin with 128.120.

Prepare Host Name Registration Request File

It is possible that on-line host name registration will be available in the future. For now, you must register host names by e-mail. Send all host name requests to hostclerk@ucdavis.edu

Your host name requests will be stored in a file and processed by a program. You must use a specific syntax in your host name request. For more information about the syntax, refer to the Net21 Host Name Registration Examples in this section and/or see More About the Host Name Request Syntax below.

Include your Employee ID number and your current UCDNet subnet number in your host name request. Note: If you are uncomfortable giving your Employee ID in an e-mail message, please give your full name instead.

Also include the projected date of your Network 21 cutover.

For each host, specify two items on a single line, separated by whitespace ( i.e., space characters or TABs ). The two items are:

Send E-mail to Host Name Clerk

Send all host name requests to hostclerk@ucdavis.edu Your host name registration file will be processed by a program. It is important that you send your information as regular text in the body of the message. The host clerk will not be able to decode and translate file attachments ( a limitation of the e-mail reader on the system that processes the host name requests ).

If possible, send your host name registration request in about 2 weeks prior to your actual cutover date. The Host Table Clerk will run your file through a preprocessor to check for errors. You will be contacted if any discrepancies are found.

Note: If you are the administrator for more than one network subnet, please separate them in your e-mail message, or send a separate e-mail for each subnet.

Once any discrepancies have been resolved, your host name requests will be queued for processing on your cutover date.

You will receive a confirmation notice when your host name registrations have been completed.

Net21 Host Name Registration Examples

Example ( Request List of Existing Host Names ):
   To: hostclerk@ucdavis.edu
   Subject: list of existing host names

   Please send me a list of existing host names.
   Employee ID:    1234578
   UCDNet Subnet:  128.120.180
Example ( New Host Names ):
   To: hostclerk@ucdavis.edu
   Subject: new host names for Network 21
   
   Please register these new host names. My Network 21 cutover
   date is 07/08/98.

   clientid 123456789
   oldnet 128.120.180   
   build leonardo.ucdavis.edu        169.237.180.1
   build rafael.ucdavis.edu          169.237.180.2
   build donatello.ucdavis.edu       169.237.180.3
   build michaelangelo.ucdavis.edu   169.237.180.4
Example ( Re-Register Host Names ):
   To: hostclerk@ucdavis.edu
   Subject: re-register host names for Network 21
   
   Please re-register these host names. My Network 21 cutover
   date is 07/08/98.

   clientid 123456789
   oldnet 128.120.180   
   change leonardo.ucdavis.edu        169.237.180.1
   change rafael.ucdavis.edu          169.237.180.2
   change donatello.ucdavis.edu       169.237.180.3
   change michaelangelo.ucdavis.edu   169.237.180.4 
   
Note: This assumes that the existing UCDNet IP addresses belong to hosts in your department. (You cannot use host names from IP addresses outside your department.)

When your UCDNet subnet is retired, host names that have not been re-registered as Network 21 IP addresses will be released automatically and will be available for others to use for IP addresses. As a courtesy, you may send an e-mail message to the Host Name Clerk to explicitly abandon host names that you no longer plan to use.

Example ( Release Host Names ):

   To: hostclerk@ucdavis.edu
   Subject: release host names
   
   Please release these host names. My Network 21 cutover
   date is 07/08/98.

   Please release these host names:
   
   clientid 123456789
   oldnet 128.120.180   
   destroy mac1.ucdavis.edu
   destroy mac2.ucdavis.edu
   destroy pc1.ucdavis.edu
   destroy pc2.ucdavis.edu
   
You may combine new registration, re-registration and release commands in a single e-mail message.

Example ( New, Re-Register and Release Host Names ):

   To: hostclerk@ucdavis.edu
   Subject: host names for Network 21
   
   Please register these host names. My Network 21 cutover
   date is 07/08/98.

   clientid 123456789
   oldnet 128.120.180   
   build leonardo.ucdavis.edu        169.237.180.1
   build rafael.ucdavis.edu          169.237.180.2
   build donatello.ucdavis.edu       169.237.180.3
   build michaelangelo.ucdavis.edu   169.237.180.4
   destroy mac1.ucdavis.edu
   destroy mac2.ucdavis.edu
   destroy pc1.ucdavis.edu
   destroy pc2.ucdavis.edu
   

More About the Host Name Request Syntax


The Host Table Clerk will use the information in your e-mail message to prepare a file with your host name requests. The file will be processed by a program. The Host Table Clerk will run your file through a preprocessor to check for errors. Once any discrepancies have been resolved, your host name requests will be queued for processing on your cutover date.

The e-mail message you send to the Host Table Clerk should contain a series of host name registration commands.

Begin your requests with a 'clientid' and a 'oldnet' command. You may then add as many 'host', 'delete', 'cname' and 'mx' commands as needed.

An example file might look like this:

  clientid 123456789
  oldnet 128.120.226
  change blythe.ucdavis.edu 169.237.42.1
  build clientid mojave.ucdavis.edu 169.237.42.2
  cname cibola.ucdavis.edu mojave.ucdavis.edu
And the confirmation might look like this:

Reply to : hostclerk@ucdavis.edu
From: hostclerk@ucdavis.edu
To: [requester]@ucdavis.edu

As requested, hostnames listed below have been registered and will become effective after 5:30 pm today.  Hostnames whatchacallit.ucdavis.edu and someonesname.ucdavis.edu are currently register.  Please revise your hostname selection and resubmit your request.  Please state time constraints, if any.

Regards,

UCD Host Name Clerk

Possible Commands:

clientid employeeid
oldnet aaa.bbb.ccc
build hostname aaa.bbb.ccc.ddd
change hostname aaa.bbb.ccc.ddd
destroy hostname
cname aliasname realname
mx hostname exchanger

Brief Descriptions of the Commands:

clientid employeeid
Specify your Employee ID number. Use this command only once, at the beginning of your host name request list.

Note: If you are uncomfortable giving your Employee ID in an e-mail message, please give your full name instead.

Example: clientid 12345678

oldnet aaa.bbb.ccc
Specify your current UCDNet subnet. Use this command only once, right after the 'clientid' command. The 'oldnet' command must be included before any updates can be accepted.

Example: oldnet 128.120.180

build hostname aaa.bbb.ccc.ddd
This is the actual host name registration command. Specify the host name you have selected, the new Net21 IP address assignment, the type of network device and the type of operating system.

The host name and IP address are required.

Example: build leonardo.ucdavis.edu 169.237.180.1

How the command is processed:

  1. If the specified host name does not exist, it is created with the specified address, cputype and ostype.
  2. If the specified host name already exists and has an address on the old subnet, the address will be updated to the new address; the clientid, cputype and ostype will also be updated.
  3. If the host exists and does not have an address on the old subnet, no changes are made.
  4. If the specified address is already in use by another host, no changes are made.

destroy hostname
If the specified hostname exists and has an address on the old subnet, the hostname is deleted from the database.

Example: destroy pc1.ucdavis.edu

cname aliasname realname
Some network devices have more than one host name. An additional host name is called an alias name. You can add an alias name (CNAME record) to an existing host name. Just like regular host names, an alias name must be unique in the ucdavis.edu domain.

Example: cname cibola.ucdavis.edu mojave.ucdavis.edu

mx hostname exchanger
Some network devices require a special DNS record to assist with e-mail delivery to their host name. You can add an MX ( mail exchanger ) record to an existing host name. Both 'hostname' and 'exchanger' must be existing host names. Use this command to create an MX record; e-mail sent to 'hostname' will be forwarded to the 'exchanger' host name.

Example: mx vermicelli.ucdavis.edu pasta.ucdavis.edu


How to Dream Up a Host Name


In general, a host name should be about 8-12 characters long, without special characters. It is permissible to use host names shorter than 8 characters or longer than 12 characters. You may use letters, digits and dashes ( '-' ) in your host name; do not use underscores ( '_' ) or other special characters.

A formal, fully qualified host name will always end in 'ucdavis.edu'. Examples of host names already on UCDNet:

isun.ucdavis.edu        gopher.ucdavis.edu       terrapin.ucdavis.edu
chip.ucdavis.edu        news.ucdavis.edu         vermicelli.ucdavis.edu
request.ucdavis.edu     directory.ucdavis.edu    shakedown.ucdavis.edu
monet.ucdavis.edu       ftp.ucdavis.edu          minglewood.ucdavis.edu
There are many ways to come up with host names. You can let each person choose the host name for their computer. You may choose to name a computer by its owner's name. You may choose to name computers by a person's job function.

It can be fun to name computers according on a theme. For example, hosts at I.T. Express are named after types of pasta; hosts in the I.T. Scientific Visualization lab are named after famous painters.

Just like an IP address, each host name must be unique in the 'ucdavis.edu' domain. You should check a prospective new host name against the names already registered in the 'ucdavis.edu' domain.

To do this, login on one of the I.T. UNIX hosts (e.g, isun.ucdavis.edu) and use the 'nslookup' command. Example:

chip% /usr/sbin/nslookup monet
Server: localhost
Address: 127.0.0.1

Name: monet.ucdavis.edu
Address: 128.120.4.10


chip% /usr/sbin/nslookup vermicelli
Server: localhost
Address: 127.0.0.1

Name: vermicelli.ucdavis.edu
Address: 128.120.180.80


chip% /usr/sbin/nslookup foobar
Server: localhost
Address: 127.0.0.1

*** localhost can't find foobar: Non-existent domain
In these examples, 'monet' and 'vermicelli' are already registered; you cannot select either of those names for your new host name. 'foobar' is available.

Note: The information in this document is specific to configuration for Network 21 cutover. For more information about IP Addresses and UCDNet configuration consult the on-line document: ‘NAR FAQs: Internet/UCDNet: Software and Information'


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Last modified 6/10/98