Recipe 8.21. Configuring NNTP for Newsgroup FeedsProblemYou want to use set up a newsgroup feed and populate the Exchange Internet Newsgroups public folder hierarchy. SolutionUsing a graphical user interface
DiscussionThe Exchange 2000 NNTP implementation is a functional (though no-frills) implementation of the NNTP protocol and it hasn't changed appreciably in Exchange Server 2003. You should always gain explicit permission from your news peers before configuring a feed, although many ISPs offer a newsgroups feed as part of a high-bandwidth (T-1 or higher) circuit package. You should never need to create NNTP feeds to propagate groups within your Exchange organization; the public folder replica and replication mechanism provides finer control and follows your organization's routing group topology. As such, there should usually be one well-defined interface between your Exchange organization and external news feeds. Also be aware that NNTP feeds can only be used for groups under the Internet Newsgroups folder in your default public folder tree; they cannot be used to replicate other public folder hierarchies with foreign systems. News feeds are asynchronous by default; any articles generated within your organization propagate to external news server through outbound feeds, while all externally originated messages come in through incoming feeds. In addition, incoming feeds have two types:
It is not uncommon to configure multiple Exchange news feeds for a peering agreement with a single provider. Many newsgroup providers have large farms of high-speed dedicated news transit servers for redundancy; your organization may need to permit incoming connections from multiple servers (news01, news02, news03, etc.), all of which will use the same Path ID header to prevent replication loops. The corresponding outgoing feed will often go to yet another FQDN, usually a DNS CNAME pointing to multiple servers. When configuring these kinds of peering feeds, be sure to adjust the unique path ID generated by the remote server field on the General tab of the feed property sheet. Although you can adjust the feed subscription on both push and pull feeds, it is only relevant to pull feeds; push feeds will accept all messages given to them, so be sure the peer has an accurate list of which groups to offer. Group subscriptions can be fully qualified group names (e.g., news.admin.net-abuse.blocklisting) or simple wildcard pattern matches (e.g., news.admin.* provides all of the groups in the news.admin hierarchy). The interaction between the NNTP flood-fill protocol and public folder flood-fill replication can provide all sorts of potential trouble if you have feeds with multiple external peers. While having multiple peers is a traditional method to ensure faster, more complete Usenet propagation, you should be careful to use the same server to handle all feeds involving a given group to avoid the potential for replication errors and loops. This practice also ensures that you will never have more than one copy of a given message transmitted to your organization, thus saving bandwidth. Using Exchange directly to exchange newsgroups with external systems may not be the right solution for your organization. A full Usenet feed transmits over 1 TB of data per day, most of which is binary groups, and the use of the NNTP streaming protocol extensions can make a noticeable difference in the speed and quality of newsgroup propagation over WAN links. If you require a full feed, specialized filtering (such as anti-spam or anti-virus checking), efficient use of your WAN bandwidth, or a greater level of redundancy for your newsgroups feeds, then you should probably investigate using specialized NNTP transit software on a dedicated host to handle your newsgroup feeds from the outside world. You can then provide a sanitized feed from this machine to your Exchange organization over your local high-bandwidth network. Additionally, you can investigate the use of the Exchange master/subordinate feed settings, which allow you to establish a group of Exchange servers that loosely work together as a single entity. Since the NNTP service cannot be clustered, this allows greater redundancy for the organization. See AlsoMS KB 266652 (How to Configure the NNTP Service, Part 1), MS KB 268092 (How to Configure the NNTP Service, Part 2), MS KB 319346 (How to create and manage newsfeeds in Exchange 2000 Server), and MS KB 328453 (HOW TO: Increase NNTP Reliability by Using a Master/Subordinate Arrangement in Exchange 2000 Server) |