Chapter 12 - Maintenance Tasks
This chapter describes domain names and name servers, and summarizes maintenance tasks you perform once you get your TCP/IP option running on your server.
You manage domain name settings for your server from the Manage Domain Name Settings selection through the Manage Communications menu at the server console. The Manage Domain Name Settings menu allows you to:
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Select a host ID ![]()
Specify a hostname ![]()
Specify a default domain name ![]()
Manage name servers
The host ID for your server is the IP address by which other hosts in the network know a server or a multihomed server. A multihomed server has multiple IP addresses.
You select your server's host ID from a list of the server's IP addresses. The following fields display for each address:
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Interface-The name of the interface with which the address is associated. ![]()
Slot-The number of the slot in which the interface's LAN card is installed. No slot number is displayed for the VINES interface. ![]()
IP address-The IP address of the interface, which you set when you managed the network interfaces.
The hostname for your server is the name by which other hosts in an IP network recognize the server. Hostnames consist of labels, which are separated by periods. The series of labels in a hostname reflects the hierarchical structure of the domain name system. The hostname begins with a label that identifies a host, an administrative group, or an individual user. The suffix of labels identifies the various levels in the host's, group's, or user's domain. A domain is a logical grouping of hosts, groups, or users.
For example, the hostname:
nsrv1.compdept.coll.univ.univnet
identifies a VINES server, nsrv1, in the domain compdept.coll.univ.univnet. This domain has four levels, or labels, with compdept at the lowest level, and univnet at the highest level.
Hostnames are not case sensitive and they can contain up to 255 characters. Valid characters include all alphanumeric characters and the hyphen.
Levels, or labels, can contain up to 63 characters. They must start with a letter and end with a letter or digit.
The default domain name is the domain name your server appends to hostnames when they do not contain domain names. In most cases, your server uses the domain portion of its hostname as the default domain name. For example, if your server's hostname is vinesgateway.company.com and you send mail to user@host2, the mail program appends company.com to host2 unless you specify a different default domain name.
Domain names can consist of labels, which are separated by periods. For example, the following domain name consists of four labels:
compdept.coll.univ.univnet
Each label can contain up to 63 characters. Labels can start with a letter, and end with a letter or digit.
You can view, add, modify, and delete name server definitions. A name server definition consists of the name server's name and its IP address (or one of its IP addresses if it is multihomed). Your server queries name servers when, for example, a third-party service needs the hostnames or IP addresses of other hosts. The name server resolves IP addresses and hostnames.
Name server definitions consist of the following fields:
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The server's host ID, or IP address ![]()
The server's hostname
You add name servers in the order in which you want your server to query them. For example, if you want your server to query two name servers, you should add the one you want your server to query first before you add the other one.
You can also modify a name server definition or delete a name server definition.
When you modify a name server definition, you specify:
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The name server's IP address ![]()
The name server's hostname
When you manage domain name settings, you see:
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The server's host ID, or IP address ![]()
The server's hostname ![]()
The server's default domain name ![]()
The number of defined name servers
Backing Up the Configuration File
Perform regular system backups on your server. The TCP/IP configuration file is always backed up during system backup. If the file is deleted from memory during a major system failure, you can use your most recent backup to restore it.
Refer to Server Operations Guide for more information on backing up and restoring files on the server.
The TCP/IP configuration program lets you control certain aspects of TCP/IP, as follows:
Enable and Disable Interfaces - This function can be useful when, for example, you have to remove the card that the LAN interface uses, and you want the interface to be disabled while the maintenance operation is performed. Chapter 8 provides more information.
Enable and Disable ARP - This function can be useful when, for example, no other hosts on a LAN support ARP, and you want to disable ARP requests from an IP interface so that unnecessary traffic is not generated. Chapter 8 provides more information.
Enable and Disable Directed Broadcasts - You may want to disable directed broadcasts if your server has been receiving an inordinate number of broadcast packets destined for IP networks directly connected to your server. Chapter 9 provides more information.
Obtaining Information on TCP/IP
You can obtain information on:
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The TCP/IP configuration, through the TCP/IP configuration program. For example, you may need this information when you need to give another network manager IP addresses assigned to your server's interfaces. ![]()
TCP/IP activity, through MNET. See Monitoring and Optimizing Servers for more information.
Modifying the TCP/IP Configuration
You may have to use the TCP/IP configuration program to modify your TCP/IP configuration. For example, if you install a new LAN card in your server and you want IP to route traffic over that LAN, you have to configure the LAN interface by means of the configuration program.
You must also modify the TCP/IP configuration when you move a LAN card used by IP to a new slot. Interface information, ARP entries, and route entries associated with the LAN card can no longer be used once the card is moved. You must re-enter this information in the TCP/IP configuration as follows:
1. Once the card is installed and configured in the new slot, add a new interface for the card. Re-enter the same information, such as IP address and subnetwork mask, that is associated with the old interface.
2. Re-enter any ARP entries, specific routes, and direct routes associated with the interface. Use the same information that is associated with the old ARP entries, specific routes, and direct routes.
3. Delete the old interface.
Chapter 8 and Chapter 10 provide information on adding and deleting interfaces, ARP entries, specific routes, and direct routes.