Chapter 6 - Planning for Specifying TCP/IP Servers
To integrate the routing functions of VINES and IP, you must associate the names, serial numbers, and IP addresses of servers. You enter these parameters when you run the TCP/IP configuration program and select one of the following two options:
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Manage Routing through VINES Networks (see Chapter 10) ![]()
Manage Server-to-Server Connections (see Chapter 11)
This chapter describes what information you need to collect to fill in these screens properly. You enter the information on the TCP/IP Server Information Worksheet.
This chapter also describes how to plan for automatic connectivity. Automatic connectivity can be enabled for either TCP/IP option.
If your server has the TCP/IP Routing option installed, you need the names and serial numbers of all the other servers in your VINES network that have the Routing option. If your server has the TCP/IP Server-to-Server option installed, you need the names and serial numbers of all the servers outside your VINES network that have the Server-to-Server option.
For each server that has a TCP/IP option, collect the following information:
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The name of the server. The name is found on the server console on either the System Maintenance menu or the Operator menu. ![]()
The serial number of the server. The serial number is also found on either the System Maintenance menu or the Operator menu. ![]()
The IP addresses associated with each server. These are found on the IP Interfaces worksheets discussed in Chapter 4. Note: Servers can have more than one IP address. See the next section, "Deciding Which IP Address to Assign," for more information.
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Which TCP/IP options are running on the servers in your network. The servers may be running either the Routing option or the Server-to-Server option, or both.
For each server in your network that is running a TCP/IP option, fill out an IP Interfaces worksheet, as described in Chapter 4. You use the information on these worksheets to fill out the TCP/IP Server Information Worksheet.
Deciding Which IP Address to Assign
Servers may have a single IP address or multiple IP addresses. For servers that have only one IP address, associate that address with the name or serial number of the server.
Typically, end points have only one IP address. Gateways usually have more than one IP address.
For Setting Up the Server-to-Server Option
If you are setting up a server-to-server connection with a server outside your VINES network, and your server has more than one IP address assigned, choose the IP address that meets the following criteria:
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The address is associated with a physical interface. Do not choose an IP address associated with the VINES interface. ![]()
The address is shared with a foreign host gateway.
Be sure that the foreign host gateway connects to the server with which you want to establish a connection.
For Setting Up the Routing Option
You should carefully plan which IP address you specify for servers in your VINES network that have the Routing option. Base your choice on how you want to set up your routing table. The TCP/IP configuration program can define routes to destinations automatically, using the network number of the IP address you choose.
For example, you enter the IP address:
130.133.2.1
The TCP/IP configuration program defines a route to network 130.133.
Choose an address containing the number of a network that your server must reach. In some cases, the server may have several IP addresses that meet this condition.
You can assign one IP address to the VINES interface with this option. This is necessary if communication is being directed to workstations running the VINES Transport version of PC/TCP.
For example, a server named Sales may have interfaces to Ethernet and ProNET-10 with IP addresses containing different network numbers, as follows:
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130.133.2.1 - Address on Ethernet ![]()
135.124.1.1 - Address on ProNET-10
In such cases, choose an IP address with:
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A network number that does not appear in an IP address already assigned to an interface on your server ![]()
A network number that does not appear in an IP address already assigned to another server in your VINES network
For example, in Figure 6-1, Your Server is connected to Sales via a VINES network.
The TCP/IP configuration program on Your Server can define a route to 130.133, using Your Server's address on Ethernet. Therefore, you do not specify Sales's address on Ethernet. Instead, you specify Sales's address on ProNET-10, which the TCP/IP configuration program on Your Server can use to define a route to network 135.124.
Deciding Which Encapsulation Type to Use
You can use IP or UDP encapsulation. On a StreetTalk for Windows NT server, you must use UDP encapsulation. On a VINES server, you can use either UDP or IP encapsulation.
In a mixed network having both VINES and StreetTalk for Windows NT servers, use UDP encapsulation to allow all servers to communicate. In a network of VINES servers only, IP encapsulation involves less overhead but you can use UDP.
See Chapter 1 in the StreetTalk for Windows NT Administrator's Guide for a discussion of Server-to-Server UDP.
Planning Automatic Connectivity
Both the Manage Routing through VINES Networks menu and the Manage Server-to-Server Connections menu allow you to enable and disable automatic connectivity. Automatic connectivity allows your server to establish connections and routes with many other servers without your manually specifying each server.
Figure 6-2 shows a simple use of the automatic connectivity feature for the TCP/IP Server-to-Server option.
Server 1 contains the VINES Mail service for the entire network. In order for all 41 servers on the other side of the foreign host to use the mail service on Server 1, they must establish a server-to-server connection with your server.
There are two ways to establish these connections:
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Configure manual entries for all 41 servers with which you want to establish connections. ![]()
Enable automatic connectivity. This allows the administrators of each of the 41 servers to connect with you by creating an entry for Server 1 through the Manage Server-to-Server connections menu. The connections are established whenever these servers attempt to communicate with Server 1. Note: One side of a server-to-server connection must be explicitly defined.
Automatic connectivity is also useful on servers running the TCP/IP Routing option. Consider Figure 6-3.
In order for the PC/TCP workstations in the VINES network to transfer files to the TCP/IP host, Server 3 must have the TCP/IP Routing option. The administrator of Server 3 can choose either of the following options:
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Manually configure an entry for Server 2, and for each of the 200 PC/TCP workstations in the network. ![]()
Enable automatic connectivity. This allows the administrators of each of the other 40 servers to route through Server 3 by creating an entry for Server 3 through the Manage Routing through VINES Networks menu. A route is established from Server 3 to whichever server routes IP traffic through Server 3.
When to Use Automatic Connectivity
Automatic connectivity should be used primarily for situations where the administrator wants to make resources available to a large number of end nodes on a temporary basis. When resources are to be made available on a permanent basis, you should manually configure your routes instead.
Only one network route is automatically created. Once the network route is created, all other automatically created routes are host routes. A result of this is that automatic connectivity, when used for permanent connections, can lead to inefficient use of server memory. Figure 6-4 shows a situation where using automatic connectivity could prove inefficient.
In this configuration, suppose that Workstation 1 logs in to the TCP/IP host. After successful resolution of all the ARP transactions, Server 3's routing table has entries for:
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A host route from Server 3 to Server 1 ![]()
A network route to 135.100.31, which is the network on which Workstation 1 resides
As long as Workstation 1 retains this connection, when any other workstation logs in to the TCP/IP Host, routes are created as follows:
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If the workstation is on the same IP network and subnetwork as Workstation 1, no additional routes are created. Server 3 forwards packets destined for 135.100.31 to Server 1, which then forwards the packet to its destination. ![]()
If the workstation is not on the same IP network and subnetwork as Workstation 1, Server 3 constructs a host route to that workstation. For example, if a PC/TCP workstation in network 135.100.32.0 logs in, a host route to that workstation is created.
In the worst case, your server might have to construct 200 host routes, one for each workstation in network 131.100.32.0. This would prove very inefficient.
A better way is to construct a network route manually to 135.100.32. This route is used to reach the workstations in 135.100.32.0. This prevents your routing table from growing large through the accumulation of host routes.
Securing Automatic Server-to-Server Connections
Enabling automatic connectivity on a server with the TCP/IP Server-to-Server option allows any other server to establish a connection to that server. Therefore, you should carefully consider how enabling automatic connectivity will affect your network's security. You can limit access to the server's resources by running the Operate utility and selecting the Restrict Access option. See Managing VINES Security for more information.
When a server connects to your server, your server then has access to whatever hosts and gateways can be reached through that server.
The network manager of Server 1 in Figure 6-5 must decide on the IP address to enter for Server 2 and Server 3.
Since Server 1 has both the Routing and the Server-to-Server options installed, Server 1's network manager must:
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Associate the name or serial number of Server 3 with the appropriate IP address. This must be done because Server 3 has the Routing option installed and resides in Server 1's VINES network. ![]()
Associate Server 2's name or serial number with Server 2's IP address. This must be done because Server 1 has the Server-to-Server option installed.
These servers have an IP address assigned to each of their interfaces, as shown in Figure 6-5.
For each server, Server 1's network manager enters the IP address containing the number of a network or subnetwork that Server 1 must reach, as follows:
Filling Out the TCP/IP Server Information Worksheet
On the TCP/IP Server Information Worksheet provided in Appendix A, record the server names, serial numbers, and IP addresses for each destination server equipped with TCP/IP. Use this worksheet when you run the TCP/IP configuration program to enter the server name/IP address or serial number/IP address pairs. You need this information for the tasks of managing routing through VINES and managing server-to-server connections, as explained in Chapter 10 and Chapter 11, respectively.
Record the following information on the TCP/IP Server Information Worksheet for each server:
Worksheet for Server - The name of the server you are configuring.
Server Name - The name of the server to which you are assigning the IP address. Names are assigned to servers when they are installed.
Serial Number - The server's serial number.
IP Address - The server's IP address.
Subnetwork Mask - The subnetwork mask for the IP address.
Option - The option installed on the server. Write R for Routing, S-S for Server-to-Server.
The sample TCP/IP Server Information Worksheet in Figure 6-6 shows how the network manager of Server 1 recorded the names, serial numbers, and IP addresses of Server 2 and Server 3.
Note: Server 2 has both the TCP/IP Routing and Server-to-Server options installed. The administrator of Server 1 is only interested in offering the Mail Services of Server 2. Therefore, only the Server-to-Server option is listed in the Option column.