A 3: Configuring EtherShare as an AppleTalk network router
The HELIOS "netconf" utility offers a very convenient user interface for network configuration.
Note that HELIOS "netconf" only is a configuration tool. Messages, like information about whether "Automatic configuration" is possible or not, are issued by the respective server programs, not by "netconf" itself.
"netconf" automatically recognizes and displays the network interfaces that are supported by EtherShare, i.e. Ethernet, FDDI, and Token Ring. Even though it is possible to enter new interfaces not yet known to EtherShare, you should keep in mind that these new interfaces may, under certain conditions, cause a system crash.
You do not need stop EtherShare before configuring your interfaces and zones with "netconf". However, you have to stop and start EtherShare after the work is done in order to let the new configuration take effect.
A 3.2 Example network setups
The following figures show example network setups with one NIC (Network Interface Card) up to four NICs:
Figure
A-8 shows a network setup comprising a server (with one NIC), two clients, and a network printer. This configuration is simple because all nodes are attached directly to the bus.
Fig. A-8: Network with 1 NIC
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Internet with router and two NICs
In the second example configuration the setup again comprises one server, but now with two NICs. The server has to link two networks, which enclose two clients each. Additionally, a network printer is connected to one of the "single" networks (see figure
A-9).
A set of
single networks, linked together by routers and forming a larger network, is called
internet.
Fig. A-9: An internet with 2 NICs and one router
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Internet with two routers and 2+2 NICs
In the last example configuration (figure
A-10) three single network segments form an internet. Two servers route the networks via four (2+2) NICs. The nodes (see
Node in chapter
A 11: "Glossary") in each segment are accessible from any other network in this particular internet.
Fig. A-10: An internet with 2+2 NICs and two routers
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A 3.3 Network automatic configuration option
If your EtherShare host only has a single network interface, or you do not want to configure EtherShare as a "seed device" (see below), EtherShare's AppleTalk protocol stack can be configured to "interrogate" network numbers and zone information automatically each time it loads, and thus avoid the necessity of manually specifying these parameters during EtherShare configuration. This situation is automatically recognized by the install script. If automatic configuration is possible, you will get the following message when you select the menu item
Configure AppleTalk network numbers:
This system has only one network interface installed, thus there is no need to configure any network numbers
If only one interface is existing, the installation program does not allow manual configuration with "netconf".
Note: The "Automatic configuration" option requires other AppleTalk routers to be connected up and online during EtherShare startup. If it does not detect any available external routers it starts in single-network mode.
For all EtherShare-supported UNIX operating systems (except for Linux) , the "Automatic configuration" option is also allowed if you have more than one network interface.
In such cases, you can allow automatic configuration by omitting the
Configure AppleTalk network numbers
step during installation.
Automatic configuration is enabled by a simplified interface specification in the EtherShare main configuration file "atalk.conf" as follows:
atalkd: if=<interface name>
Example for Solaris 2.x with a single Ethernet interface:
Example for Solaris 2.x with two Ethernet interfaces:
The entries are inserted automatically by the "install" script for all recognized hardware interfaces.
To reinstate automatic configuration after you have already configured the interfaces with
Configure AppleTalk network numbers during EtherShare installation, you need to edit "atalk.conf" manually and insert appropriate entries as shown above - or start "netconf" as described in chapter
A 3.5 "Manual network configuration".
A 3.4 Seed routers, non-seed routers
If, in addition to EtherShare, your network includes other, external routers, or if it includes certain other types of AppleTalk entities such as a "Novell Netware for Macintosh" file server, then it is necessary to specify network numbers and zone information for each physical segment in your network. Routers are configured in accordance with the manufacturer's instructions. The EtherShare configuration is described below.
When you consider an example network with two stand-alone routers, you can either "hard-configure" both routers with identical zone information, or configure one of them to "interrogate" the zone information broadcast by the other one. In the first case, both routers are so-called "seed" routers. In the latter case, one of the routers is a "seed router", since it is responsible for broadcasting the zone information, and the other router is a passive, "non-seed" device.
The latter case requires less work, because you only have to hard-configure one of the routers. If you change the configuration of the seed router, the non-seed router automatically reconfigures itself after a short delay. Of course, this will require EtherShare to be restartet.
However, the first case is technically safer because the network is left completely without zone information if the seed router fails or loses power. This can cause serious disruption of your entire network.
EtherShare can be configured as a "seed" device by manually configuring the network connection as described below. However, even if you have chosen to use EtherShare's "Automatic configuration" option instead, it is still not a true non-seed router, because it only "interrogates" network numbers and zone information of the local network segments once, when the AppleTalk module loads, and not on-the-fly like a conventional non-seed router. Nonetheless, it always adjusts automatically to changed network numbers and zone names of remote network segments (on the far side of external routers), of course.
A 3.5 Manual network configuration
Automatic configuration is described earlier in this appendix, and also in chapter
4 "Installation". Manual configuration is only necessary if automatic configuration is not possible or not desired.
The
Configure AppleTalk network numbers option of the installation script edits the EtherShare configuration by calling the routine "$ESDIR/netconf". We strongly recommend that you configure your network connection in this way, and not by editing the "atalk.conf" file, because "netconf" checks the validity of your entries, and in particular the use of valid network numbers.
Note: If required, you may see paragraph atalkd in chapter
8.3 "The AppleTalk protocol stack" for technical details of network configuration parameters in "atalk.conf".
Start "netconf" with the Configure AppleTalk network numbers option of the installation script. Alternatively, if you have already finished the installation and quit the installation script, you can start "netconf" with the following UNIX command:
cd /usr/local/es (or current EtherShare directory)
./netconf
Important: You should not run "netconf" from a terminal connection on one of the Macintosh computers. Always run it on the host's console. Otherwise, you cannot stop and restart EtherShare after you have finished (using "stop-atalk" and "start-atalk"), because the "stop-atalk" command would cut the connection to the server.
The "netconf" startup screen shows the program's main menu (see figure
A-11).
Fig. A-11: Main menu of the "netconf" program
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The following keys are available to handle the "netconf" program:
- TAB key: navigate within a "netconf" dialog
- CTRL -J, CTRL -K (or ARROW keys): navigate within a list of items
- "+" and "-": (un)mark items from a list
- ESC key: quit the current dialog
Further keys that are required in a specific dialog only, are listed in the bottom line of the respective dialog. Alternatively, they are described in the help windows.
"netconf" includes a convenient online help system which can be activated by pressing "?". An example is shown in figure
A-12.
Fig. A-12: The "netconf" online help system
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- "netconf" gets its information from the "atalk.conf" file.
- If you are making an upgrade installation, the "install" program automatically preserves your previous "atalk.conf" file so that previously entered zone, network, and printer information, etc. do not get lost.
- If you de-activate one interface temporarily, the configuration will also be saved in "atalk.conf", and will be available again on re-activating the interface.
- If you have an IBM RS/6000 host, note that two logical interface names exist for each card. "et0" is used for AppleTalk (and is used by EtherShare), and "en0" is used for TCP/IP. You should see in the list an "et0" entry for the AppleTalk connection and an "tr0" entry if your host has a "Token Ring" interface as well.
The
Configure Adapter option from the main menu lets you see the list of interfaces that are available.
Figure
A-13 shows a network with one single interface only, where no configuration is necessary. If you pressed RETURN in order to open the configuration dialog a corresponding information message would pop up.
Fig. A-13: The "No need to configure" information message
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List of
interfaces / Adding an interface entry
Figure
A-14 shows a network with two interfaces. As mentioned before, "netconf" automatically checks for all recognized Ethernet interfaces in your host and shows them on the screen. If an interface cannot be recognized it will be missing in the list. In that case, you can press CTRL-V (on some machines it may be necessary to press CTRL-V two times) to open a dialog that lets you enter a new interface. This dialog is shown in figure
A-15. For instructions on how to fill in the dialog, please read paragraph
Changing an interface entry below.
Remember that for a new entry, you need to know the correct name of the interface and whether it supports AppleTalk. Incompatibilities may cause system crashes.
Fig. A-14: Network with two interfaces
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Fig. A-15: Creating a new interface entry
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Changing an interface entry
If you want to change the configuration of an existing interface, you have to switch off automatic configuration by using the "a" key, and then press RETURN.
Note that you can enter a manual configuration and then switch between
active and
non-active. The manual settings will be stored in the "atalk.conf" file when you switch on automatic configuration, and they will be available when you switch automatic configuration off again.
Figure
A-16 shows the dialog window that lets you change the configuration of a particular interface.
Fig. A-16: Changing the configuration of interface "le0"
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In the above dialog, you have to enter a network number range from
Start - End, where
Start can be equal to
End.
If you have either an external or an internal router, a valid number for
Start and
End is any number between 0 and 65279. Numbers between 65280 and 65534 are only used if you do not have a router, otherwise they are reserved. Note that EtherShare provides an internal router automatically if you have more than one network connection, as in this example.
Each range, e.g.
10-10, allows approx. 250 entities (nodes).
The correct choice of the network number range is subject to the following restrictions:
- If you have no router (i.e. only one internal Ethernet connection in your host and no other, external routers) do always use the "Automatic configuration" option.
- If you want to connect your host to an external router box on the same network segment (cable), you must use the same network number range (Start - End) and the same zone names in the same order as the router. Please refer to the router's manual to find out how to determine its configuration. This is often done with a configuration program on a Macintosh attached to the router.
- If an external router broadcasts information that differ from the configuration you have entered, you will receive a warning when EtherShare starts. The system will always rely on the router's information, in that case, and will ignore your entries.
- If your host has more than one network connection, as in this example, network numbers and network number ranges must be unique and must not overlap each other or those of other, external routers to which you do not want to establish a connection.
- If you have two internal Ethernet interfaces and want to route between Phase II and a (rather old) Phase I connection, the network number Start must be equal to the network number End (e.g. 30-30). This may require reconfiguring external Phase II routers (if you have any) accordingly.
Note: Phase I connections are no longer supported by
EtherShare.
Proceed to the "Zones" list in the dialog and press RETURN to open a second dialog that lets you specify the name of the default zone for the current interface (see figure
A-17). You can use the "New Zone" dialog again to define additional zones for the interface later.
Fig. A-17: Entering an individual zone name
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When entering names, please keep the following in mind:
- Zone names may have up to 31 characters.
- After entering the default zone name, you can enter additional zone names for the same network number range.
- If you want to connect your host to an external AppleTalk router box, you must use exactly the same zone name(s) in the same order as the router. Please refer to the router's instruction manual to find out how to determine its configuration. This is often done with a configuration program on a Macintosh attached to the router.
- If an external router provides one or more zone names for the local network segment, you must either specify all of them or none of them. In the latter case, EtherShare "interrogates" the router for the names. This is, however, less safe, as described in chapter A 3.4 "Seed routers, non-seed routers" above.
- If your network has more than 12 zones, they can be specified by editing the "atalk.conf" file manually.
- If you want to replace an entry, use the BACKSPACE key first to delete the existing one.
- In the "New Zone" dialog, you can use the "*" key to open a pop-up menu that shows all recently used zone names.
Figure
A-18 shows the completed dialog. The settings will be saved on selecting the
Ok button and then appear in the list of interfaces as illustrated in figure
A-19.
Fig. A-18: Saving the settings in the interface dialog
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Fig. A-19: List of interfaces showing the new settings for "le0"
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Figure
A-20 shows the dialog for the interface "le1". In that dialog, we have entered two zones, and have made the second one the default zone by pressing the SPACE key.
Fig. A-20: Adding zones to an interface and changing the default zone setting
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The final example configuration is shown in figure
A-21. The configuration includes two interfaces with two zones each. One of the zones is a shared one.
You can now press the ESC key to return to the main menu and then select item
Configure Zones to register the available zones (see figure
A-22).
Fig. A-21: Example of a final adapter configuration
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Fig. A-22: Opening the "Configure Zones" dialog
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Figure
A-23 shows the dialog that lets you register zones, i.e. specify zones where EtherShare services should be listed.
Fig. A-23: Moving entries between two lists of zones
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You can move a zone between the left and right column of the dialog by using the CTRL-L, or the CTRL-H key. This is illustrated in figures
A-23 above and
A-24 below.
Fig. A-24: Removing items from "Zones providing ES Services"
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The
Auto Zones button in the dialog can be used to make sure that for each active interface at least one of its zones is registered.
EtherShare services can only be registered in local zones, i.e. in zones that have been set up on a network segment (cable) which is directly connected to the server.
Note: The lists in the dialog ("Available Zones" and "Zones providing ES Services") would be empty if "Automatic configuration" was activated.
Priorities in
"atalk.conf"
In "atalk.conf", the line "atalkd" indicates the zones that are available. The line "zones" will be checked by all starting server processes (such as "afpsrv", "papsrv", ...) to find out in which zones they have to register. In case the line "zones" is missing in "atalk.conf", and there is no "zone=" entry for the server, the server processes will register in the default zone. The default zone can be seen when using the
zones -l command on a UNIX shell. In the list of zones, the default zone is marked by a "*".
Reconfiguring network
connections
If your network changes (on segments where EtherShare is installed) , for example if you have added a new router, you can use "netconf" again to reconfigure the network connection at a later date, without re-installing EtherShare. To do this, stop EtherShare from the host's console using the "stop-atalk" command, start the "install" program, and select menu item
Configure AppleTalk network numbers.
The connections will be active as soon as you restart EtherShare with "start-atalk".
If you have chosen the "Automatic configuration" option rather than manual configuration with "netconf", all you need to do is stop EtherShare with "stop-atalk" and restart it again - EtherShare's AppleTalk protocol stack will "interrogate" the network numbers and zone information again when it re-loads.
