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Hostmaster Services

Traditionally, Domain Name System (DNS) domains have an official hostmaster to assign hostnames to IP addresses and manage the name space. The UC Berkeley domain is Berkeley.EDU. The hostmaster function for the Berkeley.EDU domain is performed by several people within Network Services and includes these activities:

  • Care and feeding of nameservers (both hardware and software),
  • Registering IP addresses and hostnames for new network connections,
  • Coordination of network connection moves,
  • Changing assigned hostnames,
  • Adding aliases and mail-forwarding records to existing hostnames,
  • Creation of subdomains,
  • Coordination with departmental hostmasters who have been delegated authority for their own (departmental) subdomains.

IPs and hostnames for new network connections

New network connections, as well as moves, removals and conversions of existing connections (from fast to gigabit Ethernet, for example), should be requested using the CNS Shopping Cart, available at Any required DNS changes will automatically come to the attention of the hostmaster(s). When filling out the form, be sure to include any specific hostnames desired for new connections (if none are requested, we will assign names following campus convention). For connection moves, removals, or conversions, be sure to include current IP addresses and hostnames to be preserved. Also specify your department's subdomain, if any. Additions, changes and corrections to the service request form should also be sent to Communication and Network Services, Communication Consulting Unit, 2484 Shattuck Ave., 94720-1640.

Other DNS issues

All other questions about hostnames, IP addresses and the nameservers may be emailed to hostmaster@nic.Berkeley.EDU. These may include requests to rename a host, add an alias to an existing hostname, add a mail forwarding record for a host, or requests for the hostname and IP address previously assigned to a existing network connection. Queries about the integrity of data within the campus nameserver database may also be sent to the hostmaster account.

Timing of DNS changes

Requests for DNS changes may be processed at any time, though most are processed during standard business hours. The changes generally take effect shortly after 3am the next day, when the DNS servers are reloaded. Requests for specifically timed changes can sometimes be accomodated, depending on what other changes have been requested by the campus as well as Network Services' current operational workload (please give Hostmaster 5 business days' notice).


Email to hostmaster@nic.Berkeley.EDU will open a request ticket. You will receive an email autoreply with your ticket number. Please take care to include this ticket number, with formatting preserved, in the subject line of any further email concerning the request. If your request can be completed with the information provided, Hostmaster will complete it and will send a confirmation email. If it can't be completed for some reason, Hostmaster will send an email explaining the issue or requesting additional information, and will keep the ticket open until it can be resolved.

Response time

You will receive a response to your request within two business days. For routine requests, that response will be an indication that the work has been done; in many cases, this happens within one business day of the request. If your request is urgent, please indicate that in the subject and contents of your email. We will do our best to expedite emergency requests, but it's always better to give us as much lead time as possible.

Lead time

In general, advance notice isn't required for Hostmaster requests; they're processed as soon as possible. However, moving a machine to a different subnet will go much more smoothly with some advance notice and coordination. Please see the comments below concerning TTL for IP address and/or hostname changes for servers.

Also, requests for off-hours DNS changes or specially-timed nameserver reloads should be made with at least 5 business days' notice.

Moving a machine to a different subnet

When you move a machine to a new subnet, you'll need to change its IP address to an IP on the new subnet, by editing the its TCP/IP settings. This change should be coordinated with the DNS change made by Hostmaster; otherwise there will be an interval where the machine is unreachable.

This is fine for most personal workstations, since they need outbound network connectivity, but don't generally run network services which accept incoming connections from other machines. Their DNS can be changed overnight, and the machines can be renumbered the next morning (or the night before).

But in a few cases, the machine being moved is a server which must be reachable without interruption, such as a mailserver or webserver. In this case, you'll need to coordinate the timing of the IP address change with Hostmaster.

In addition, if the server is used by people outside of the university, at least two days of extra lead time is required to coordinate the change. This is because outside nameservers cache UCB's DNS records, for efficiency. Each DNS record has a specified TTL (Time to Live) interval; UCB's default TTL is currently 24 hours. On the first day, the TTL for the hostname record will be reduced to 5 minutes, so that the IP address change can be seen immediately by the outside world. On the second day, the IP address will be changed. Since this change normally happens at 3 am, please let Hostmaster know if you want to schedule the coordinated cutover at a different time.




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