Managing replication of articles          

his chapter describes how your Collabra Server can share and exchange articles with other news servers.

Understanding discussion group replication

The following sections discuss two types of discussion group replication:

• Outgoing discussion groups are discussion groups sent by your server to other servers. You specify which discussion groups your server sends to other servers.

• Incoming discussion groups are discussion groups sent to your server from other servers. After you configure your server to accept discussion groups from another server, you cannot control which discussion groups are sent to your server. You do control, however, which discussion groups your server supports. So if your server does not support the discussion group sent by the other server, all the articles in the discussion group are "rejected" by your server.

It is possible, however, to receive discussion groups from another server and not return discussion groups to the server. You must specify in your configuration that your server will not send discussion groups to the other server.

About terminology and push and pull feeds. In Usenet terminology, discussion group replication is called a newsfeed. The Collabra Server supports push feeds. That is, the server can push information to other servers and receive information that is pushed to it. The server cannot, however, pull information from other servers (known as a pull feed).

Access control and security

Access control

For more information about access control, see Chapter 3, "Controlling access to your server."

Security

Authentication verifies the identity of the client or server.

Encryption ensures that data cannot be deciphered if it is intercepted during transmission or if it is received by the wrong parties.

For more information about SSL, see Chapter 6, "Understanding security."

Incoming connections

• Receive encrypted data

• Replicate discussion groups with remote servers running in secure connection mode

You activate secure connection mode by choosing Encryption|Activate Connection Security. Before you can activate connection security, however, you must generate a key pair file and obtain and install a valid server certificate. For more information about secure connection mode, key pair files, and security certificates, see Chapter 6, "Understanding security."

About port numbers. For servers running in secure connection mode, the standard NNTP port number is 563. You should always use port number 563 for servers running in secure connection mode. You can use other port numbers, but Netscape does not recommend that you do so.

About Usenet articles. In general, Usenet articles are not encrypted and are sent on port 119, the standard NNTP port number for nonsecure communications. You cannot receive Usenet articles if your server is running in secure connection mode. You can, however, install the Netscape Collabra Server twice: one instance running in secure connection mode on port 563 and the other instance running in standard connection mode on port 119. This lets you receive Usenet news from other sites and still maintain a separate and secure environment for your private discussion groups.

Outgoing connections

The receiving server determines whether the transmission should be encrypted or not. You configure the Collabra Server to use the receiving server's port number and SSL setting for transmissions. (The Collabra Server can send to a port number other than the one to which it is listening.)

For example, assume your Collabra Server is running in secure connection mode and listening to port 563. You can configure your server to send unencrypted data to a remote server that is running in standard connection mode. For your outgoing connection to the remote server, you specify the port number that the remote server is listening to and you specify that the remote server is not using SSL.

For another example, assume your Collabra Server is running in standard connection mode and listening to port 119. You can configure your server to send encrypted data to a remote server that is running in secure connection mode and listening to port 563.

Of course, the receiving server might not be able to send to you unless it has the same capabilities as the Collabra Server; that is, unless it can specify SSL settings and port numbers for outgoing connections.

See "Configuring a replication host" for more information about configuring outgoing connections.

The benefits

From the same server, you can send private discussion groups with encryption and send public discussion groups without encryption.

Figure 5.1 shows possible communication scenarios between news servers. A dotted line indicates that the remote server can send information to the Collabra Server only if the remote server can send to a different port number than the one to which it listens. Arrows indicate whether the replication is bidirectional or one-way only. Port 563 is the default port number for news servers running in secure connection mode. Port 119 is the default port number for news servers running in standard connection mode.

Discussion group replication

Control articles

Control articles are sent just like other articles and are stored in the control discussion group. The RFC 1036 defines the format for these articles. Control articles are sent with a control header or a subject header that starts with the characters csmg.

You can specify how you want the Collabra Server to handle control articles that it receives:

• If you want manual control over any action that can affect your news server, you can specify that control articles be emailed to you for immediate appraisal on an individual basis. Or, you can specify that control articles be entered into the server log so you can review them all at once by looking at the log file.

• If you do not want manual control over any action that can affect your news server, you can specify that the Collabra Server handle control articles automatically as they are received.

  In general, it is easier to administer replicated internal discussion groups if you allow control articles to be executed automatically.

Planning your discussion group replication

1. What discussion groups do you want your Collabra Server to provide to your users?

   You will make this decision based on what kind of content you want to provide and how much disk space you have available.

2. What discussion groups do you want to replicate with other sites?

3. Are your replication sites internal to your organization or will you also be replicating discussion groups with sites external to your organization? Your answer can affect other decisions about how to handle security issues, control articles, and so on.

4. After you've decided what discussion groups you want to provide and who your replication sites will be, you must contact the administrators of any remote sites. Typically, you need to provide the following information to the administrator of the remote site:
   • The hostname (and maybe the IP address) of your server

   • Your email address so the administrator of the remote site can contact you

   • A list of discussion groups that you would like sent to your server

   • A list of discussion groups that you would like to send to the remote server

   You and the administrator of the remote site will also need to agree on the port numbers you will use, how often you will send articles, control article handling, and so on.

5. After you've done steps 1 through 4, you are ready to configure your server for discussion group replication.

Viewing information about replication

• Existing replication hosts

• Default replication settings

• Edit information about replication hosts

• Remove replication hosts

• Resend existing articles to replication hosts

• Edit your default replication settings

You can also view information about discussion group replication in the server log and the discussion replication log by choosing Reports. See Chapter 7, "Viewing and interpreting log files," for more information.

To view or specify information about how often to send outgoing discussion groups, choose Server Preferences|Technical Settings. See Chapter 2, "Specifying technical settings," for more information.

Configuring a replication host

1. Choose Discussion Replication|Configure Replication Host.

2. In the hostname field, identify the host with which your server will exchange articles. You can specify a hostname, such as secnews.netscape.com, or you can specify an IP address, such as 198.93.93.10.
   Note: If you have configured your Collabra Server not to resolve hostnames into IP addresses, you must specify an IP address in the hostname field.

3. For outgoing discussion groups, you need to specify the following:
   • Which discussion groups to send

   • The remote server port

   • The SSL setting for the outgoing connection

4. To specify which discussion groups to send, from the pull-down window, choose one of the following options:
   • All discussion groups

   • No discussion groups

   • Default discussion groups

   • Specified discussion groups

   • All but specified discussion groups

   If you choose Specified discussion groups or All but specified discussion groups, in the Discussion Groups field, type the name of the discussion group or groups.

   You can specify patterns, such as royal.*, to send all discussion groups that start with royal.

5. The remote server port is the port the receiving server uses to receive transmissions. For the remote server port, click one of the following options:
   • Use port number (same as this server). This option uses the same port number that the Collabra Server listens to. By default, to communicate with one another, standard news servers listen to port 119 and secure-connection servers listen to port 563.

   • Use this port. This option enables you to send to the remote server even if the Collabra Server and the remote server are listening to different port numbers. In the associated field, type the port number for the remote server. This option sets up your outgoing discussion groups to the remote server, but does not guarantee bidirectional replication between your server and the remote server. To send to your server, the remote server 1) must have the ability to send to a port number other than the one to which it listens, and 2) if the remote server has the ability, it must be configured to send to your server's port number.

6. For the SSL setting for the outgoing connection, click one of the following options:
   • Use SSL setting of this server. This option uses the current connection mode of the Collabra Server. You specify the current connection mode by choosing Server Preferences|Activate Connection Security. If a remote server has a different setting, any attempted transmissions to that server will generate an error message in the replication log.

   • Remote host uses SSL. This option tells the Collabra Server that the remote host uses SSL; therefore, the Collabra Server must encrypt transmissions before they are sent to the remote server. (The Collabra Server can send encrypted transmissions whether running in secure connection mode or not. )

   • Remote host does not use SSL. This option tells the Collabra Server that the remote host does not use SSL; therefore, the Collabra Server must not encrypt transmissions before they are sent to the remote server. (The Collabra Server can send unencrypted transmissions whether running in secure connection mode or not.)

     For incoming articles, you must specify information about the control articles your server receives. A newgroup control article requests that your server create a new discussion group. A rmgroup control article requests that your server delete a discussion group.

7. In the Accept newgroup field, type the discussion groups for which you will accept newgroup control articles. If you want to accept these control articles on all discussion groups, type *.

8. Specify how you want to handle newgroup control articles. From the pull-down menu, choose one of the following options:
   • create group. This option tells the Collabra Server to create the discussion group automatically. Do not use this option if you want to manually control which discussion groups are created on your server.

   • send mail to admin. This option lets you handle the control article requests on a case-by-case basis. For each control article you receive, you can decide whether you want to create the discussion group on your server.

   • make log entry. This option allows you to review all control articles and requests by looking at the log file.

   • ignore. This option tells the Collabra Server not to create the new discussion group.

9. In the Accept rmgroup field, type the discussion groups for which you will accept rmgroup control articles. If you want to accept these control articles on all discussion groups, type *.

10. Specify the action to perform on rmgroup control articles. From the pull-down menu, choose one of the following options:
    • remove group. This option tells the Collabra Server to remove the discussion group automatically. Do not use this option if you want to control which discussion groups are removed from your server.

    • send mail to admin. This option lets you handle the control article requests on a case-by-case basis. For each control article you receive, you can decide whether you want to remove the discussion group from your server.

    • make log entry. This option allows you to review all control articles and requests by looking at the log file.

    • ignore. This option tells the Collabra Server not to remove the discussion group.

11. Click OK.

Note: For each remote server that you exchange articles with, you can specify how your Collabra Server responds to the newgroup and rmgroup control articles. Therefore, it is possible to handle control articles differently for each remote host.

Editing default replication settings

1. Choose Discussion Replication|Edit Default Replication Settings. (You can also access the edit form from the View/Manage Replication Hosts form.)

2. To specify which discussion groups to send, from the pull-down window, choose one of the following options:
   • All discussion groups

   • No discussion groups

   • Specified discussion groups

   • All but specified discussion groups

   If you choose Specified discussion groups or All but specified discussion groups, in the Discussion groups field, type the name of the discussion group or groups.

   Note: When configuring a replication host, you can choose the option Default Discussion Groups.

3. Click OK.

Removing a replication host

1. Choose Discussion Replication|View/Manage Replication Hosts. The replication hosts are listed on the form.

2. Scroll to the host you want to remove.

3. Click Remove.

• Replicate your spool to a new host

• Replicate your spool to a host that has crashed or has somehow lost articles that you had previously sent to it

1. Choose Discussion Replication|View/Manage Replication Hosts. The replication hosts are listed on the form.

2. Scroll to the host to which you want to resend articles.

3. Click Resend.

4. You can specify which articles you want to send by clicking the associated button. You can:
   • Resend all available articles

   • Resend only those articles available within the timeframe you specify. In the days field, type the number of days

5. Click OK.

Handling control articles

Other control articles (checkgroups, sendys, and version) specify information about replications in general.

To specify how you want to handle these control articles:

1. Choose Discussion Replication|Control Article Handling.

2. Specify the action to perform on the following control articles:
   • checkgroups. This control article contains a list of the valid discussion groups within a specific discussion group hierarchy.

   • sendsys. This control article requests that a description of the receiving server's discussion group replication configuration to other servers be mailed to the article's reply address.

   • version. This article requests that the name and version of the receiving server be mailed to the article's reply address.

   From the pull-down menu for each article, choose one of the following options:
   • send mail to admin. This option lets you handle the articles on a case-by-case basis.

   • perform action. This option performs the action requested in the control article.

   • make log entry. This option allows you to review all control articles and requests by looking at the log file.

   • ignore. This option ignores the control article's request.

3. Click OK.