N-PLEX Global 4.0
N-PLEX Global is a sophisticated, scalable mail server. Although ISOCOR markets N-PLEX Global primarily to ISPs and large corporations, the product scales to small companies that want to take advantage of its full feature set, reliable performance, and compliance with a broad range of Internet mail standards and Requests for Comments (RFCs).
N-PLEX Global supports SMTP with extensions, POP3, and IMAP4. The product can support LDAP-based queries into the mailbox database and account replication with other LDAPv3-compliant servers in support of a centralized corporate directory; however, to take advantage of this functionality, you need to purchase ISOCOR's Global Directory Service separately. N-PLEX Global monitors mailbox disk usage for soft and hard quotas. N-PLEX Global's password policy management lets administrators require a minimum password length and allow use of uppercase, lowercase, and nonalphabetic characters in the password. N-PLEX Global stores user settings in a proprietary database structure, rather than in the NT Registry.
N-PLEX Global can use an existing NT account or a password that you create to authenticate user access to mailboxes. When you choose NT account authentication, the user's NT user ID becomes the default email address in the domain you create the mailbox in. You can create additional user email addresses as aliases in the default domain or any other domain that the mail server hosts.
Installation. I received my test copy of N-PLEX Global as a Zip library. After extracting the files, Setup guided me through the installation process and prompted me to provide a directory to install the files into and a password to use when I access administrative functions. As I let Setup reboot the system, I thought that this product was the easiest to install of all the products in this group. Then I tried to Telnet to port 25, the SMTP port, and couldn't connect. I experienced the same failure with port 110, the POP3 port. I decided to read the installation instructions.
I learned that Setup installs only the ISOCOR Management Center. I had to use Management Center to install Internet Mail. By expanding the view in Management Center's left pane and right-clicking the name of the server, I was able to see and select the Install option. The program remembered the original source path and displayed the optional components available for installation. I selected Internet Mail, and the IM installation wizard started. The wizard prompted me to enter a destination directory for mail files and choose another password for Internet mail administration tasks. After I entered the product serial number and license key, the wizard completed without requiring another reboot.
N-PLEX Global consists of seven NT services. The Mail Server, Mail Delivery Agent, Mailbox Monitor, and Message Store services support basic messaging. The software uses the White Pages synchronization service in conjunction with an LDAPv3 server, such as Global Directory Service. The software also installs the Remote Management and List Management services.
To complete the basic installation, I had to configure a mail domain and users. I expanded the IMS object in the left pane of Management Center, right-clicked Mail Domain, and selected the Add Domain menu. I typed in ntlab.com at the prompt, and the software added the domain object to the list. Adding individual users was not much more complicated. When I right-clicked the mail domain object ntlab.com, then selected Add, the Message Store User menu item displayed, and I could create individual users.
Documentation. When N-PLEX Global installs, comprehensive software documentation in PDF format installs in the program directory. You can print out the documentation. I found the table of contents for each manual in the documentation to be thorough and well organized. A Main Menu document for the four online manuals makes moving between manuals easy. N-PLEX Global's documentation is the most comprehensive and usable documentation set of any of the products in this review.
Configuration and management. A variety of account and mail-server administration options are available to N-PLEX Global users. Management Center, which Screen 5 shows, is the primary system administration tool. You can run Management Center remotely if you install the ISOCOR Remote Management Agent service on the mail server. Management Center displays a typical tree or hierarchical view of the system in the left panel. Right-clicking an item in the left panel displays a menu for that item. Selecting an item in the left panel displays objects created under that item in the right panel.
Management Center renders N-PLEX Global highly configurable. You can specify the number of concurrent send and receive threads for performance tuning. You can specify mail retransmission retry periods and direct your mail server to implement the N-PLEX Global-supported mail extensions and RFCs that you specify. Other features, such as the ability to specify the amount of free disk space that is necessary for mail-server operation, reflect N-PLEX Global's large-enterprise-class feature set. N-PLEX Global was one of the few servers I tested that supported this level of configuration granularity.
N-PLEX Global includes two Web-based management tools. One tool helps mailbox owners manage their mailbox account; the other tool assists mail-system administrators. Both tools are Java applets that require a Web server and require the ISOCOR Remote Management Agent service on the mail server.
ISOCOR supplies several utility programs with N-PLEX Global. The db_dump utility creates a copy of the mail accounts database in a readable text-file format. You can use nibl.exe to quickly dump and load large numbers of mailbox accounts.
POP, IMAP, and Web access. N-PLEX Global's POP and IMAP client access is unremarkable, and all the software's mail-management features work well. I was able to send and receive messages, create IMAP folders, and move messages between folders. ISOCOR supports Web access to email in N-PLEX Global with Web Express, a product that you must purchase separately. Because ISOCOR didn't build Web support into N-PLEX Global, Web Express requires a separate Web server to implement Web-based email.
N-PLEX Global doesn't include an LDAP server as a standard feature, and thus doesn't support LDAP queries to its directory. ISOCOR's Global Directory Service, a companion product to N-PLEX Global that you must purchase separately, is a fully LDAPv3-compliant server that adds client query support as well as LDAP directory replication with other LDAPv3 servers.
List-server features. N-PLEX Global has a flexible list-server feature that supports standard subscribe and unsubscribe commands, as well as who, which, and lists commands. The software supports moderated and unmoderated lists. Lists can be open (i.e., anyone can submit mail to the list) or you can restrict lists to mail from list members or to mail from the list moderator. For advanced list applications, N-PLEX Global lets you write your own list-management agent. The product doesn't support digested lists.
Performance. N-PLEX Global's peak performance reached a maximum throughput of nearly 64tps, the second fastest of the six mail servers I tested. In addition, the product was the only server in which throughput didn't decline significantly at loads higher than the point of maximum throughput. If you want steady performance under any load, N-PLEX Global is the product to buy.
Final valuation. N-PLEX Global is a robust mail server for high-end environments. Although the software is highly configurable with great remote-management capability, it lacks some key features, including LDAP support and support for digested lists in its list-server function. In version 4.0, I sense a vendor commitment to continue to support enhancements to email standards and maintain the high performance and reliability that the largest ISPs and businesses need. N-PLEX Global is by far the most expensive of the servers in this group, with a base price of $1000, plus $3 to $5 per mailbox. Large organizations should consider the product; other companies will be better off with one of the lower-cost packages.
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