eServ: An internationalized proxy server ideal for small-to-midsize enterprises that works with ma
In an era flooded with a spate of high-speed Internet connections, it's easy to forget those users left behind, limited to a single Internet connection for multiple users. This situation can be found worldwide, but is especially prevalent in Europe, where the high cost of phone line is exacerbated by high per-minute charges.
Thus, an internationalized tool like EServ can be valuable for individuals and companies struggling with limited connectivity to the Internet. Basically, EServ is a proxy server that routes data from the Internet to multiple machines on a local network. EServ works with mail (SMTP and POP3) and news (NNTP) servers to bring electronic mail and newsgroups to these local machines. It can run on a dedicated server or coexist on a network user's PC.This situation can be found worldwide, but is especially prevalent in Europe, where the high cost of phone line is exacerbated by high per-minute charges.
While EServ can be used with any mail and news client, its documentation provides in-depth help for configuring a wide range of mail and news clients, including popular ones (Microsoft Internet Mail, Microsoft Outlook Express, Netscape Mail, and Eudora) and those less frequently used (TheBat, Gozilla, NetVampire, and CuteFTP). As a proxy server, EServ can work with any operating system on the client side, including Windows (3.1, 95, 98, and NT), Unix, MacOS, OS/2, and DOS. Any sort of e-mail address can be used with EServ; however, the company recommends companies with multiple users obtain their own domain name (such as email@example.com), so that all messages can be forwarded to the EServ server. The EServ server will then store the messages until they are retrieved by the appropriate user.
EServ is a product from, eType, a Kaliningrad City, Russia, Internet service provider (ISP). EType was in the market for a tool that managed electronic mail for multiple users via a single Internet connection. After searching the market, the ISP decided to develop its own tool. Along the way other features were added to make EServ more of an enhanced proxy server.
Basically, EServ runs a local in-house news and mail server, and then grabs information from servers on the Internet. All users on the local network can connect to the Internet via a single Internet connection or modem (using a single IP address). EServ uses Socks 5 to manage these connections, so applications (i.e., Web browsers, FTP clients, and instant messagers) must be configured to work through this proxy server. This is not a huge task: The EServ documentation (found at http://docs.eserv.ru/) provides excellent information about how to configure these clients to work with a proxy server.
EServ can act as a Web server (for Internet or intranet purposes) and as an FTP file server when connected via a fixed IP address. (If an organization is not using EServ as a server, it can use it with a dynamically assigned IP address.) EServ can also be used to distribute mail to remote users via RAS (when running on Windows NT) or via the Internet: Remote users can connect to EServ.
EServ takes up about 3 MB of hard-disk space. It can be run as a service under Windows NT, or as a regular application under Windows 95 or 98.
EServ supports aliases for routing addresses to other mailboxes. For example, a sales mailbox can be set up to be routed to the head of the sales department. Mailing lists can be set up so messages sent to a single mailbox can be routed to multiple mailboxes. To do this, administrators need to set up a text file or edit the existing text file in EServ to specify which users should receive these messages.
If an enterprise is using EServ to work with external mail and news, it will need to set up external programs, or "robots," to send and receive news and mail messages on a regular basis. These robots can automatically respond to messages coming to specific mailboxes, send out "vacation" messages, route messages to different users or folders, and perform almost any other desired tasks. These robots are common programs that can be written in any programming or scripting language, but a schedule must be set up to run these external programs.
Setting up the news server is largely a matter of specifying which newsgroups are to be retrieved, as well as setting up any local newsgroups reserved for local users. (EServ cannot be used to set up a new newsgroup that can be retrieved from the Internet.) Enterprises can set up permissions for specific users (e.g., they may want some users to have the power to read news postings but not post anything).
Much of the set-up work for EServ is done through the Scheduler, an EServ component that runs tasks on a regular basis. Some of these tasks are quite apparent to users, including sending and receiving external mail (and sorting it) and news postings on a regular basis. Many of the other tasks are housekeeping chores, such as: cleaning out the proxy cache, reducing the size of the cache, deleting old news from the news directory, and deleting old EServ files. The conditions can be changed from task to task. Administrators can set up tasks to be run at defined intervals, such as between starts or at specific points in time. Many of these tasks are built into EServ, but users can extend this capability with external programs (written in any programming or scripting language supported by Windows NT) run from a command line.
As a pure proxy server, EServ is acceptable. When EServ is asked to retrieve a file on behalf of a local user, it stores a copy locally, and then serves it again to other users requesting the files. Like every other proxy server, EServ can be configured for how it checks whether files must be downloaded again or if it needs to be retrieved from the Internet and updated. Three settings are available for cache updating: 1) do not check to determine if the file must be updated; 2) check if the file is X number of days old; and 3) use the standard method of cache updating via TTL and HTTP/1.1, where the proxy server asks the Web server if the page has been updated and needs to be updated. (Users can also turn off caching, but that is one of the main reasons to use a proxy server.) In addition, EServ will not cache dynamically generated Web pages, and it can be set up to block access to specific Web servers.
When a user wants to access a Web site and EServ is not connected to the Internet, EServ will automatically dial the ISP and connect to the Internet. (EServ will not dial into the Internet if there is a copy of the Web page in the cache.)
For those applications and protocols that require a direct connection to a server, users need to force connections via Socks 5. (This is a standard way to allow protocols like streaming media to bypass proxy servers.) If users encounter a protocol that is not universally supported by Socks 5, they must manually map external servers into a local server. This process is not difficult but will probably not be used too often.
Finally, EServ performs all the other tasks expected of a proxy server. For example, it supports DNS caching, so the system does not need to connect to a DNS server every time a client requests a frequently requested Web page.
Administration can be performed locally or via a Web interface. The Web interface allows remote administration, which can be done from any computer on the LAN or even the Internet. (Access is password protected.) The Web interface can be edited by the system administrator.
The EServ Web server is functional but not flashy. Files can be stored in the root directory of the Web server or in virtual directories. EServ also supports virtual Web servers, so enterprises can run several network names from different subnets on the same PC. To establish virtual servers, EServ uses the Host field in HTTP inquiries to determine what Web site is being requested. Thus, there is no need for unique IP addresses for each of the network names. In addition, the EServ Web server supports the CGI interface for running external programs.
EServ stores system activity in log files. Users can view completed log files or activity in real time. The information is broken down by the date and time of the activity, as well as by the server protocol that generates the record and the name of the service. Older logs are automatically rolled over into new files.
User access tools in EServ are strong. Administrators can restrict external access to any of the configured EServ services. For example, they can limit access to the FTP server or the HTTP server to only those users who have the correct user name and password. Similarly, they can restrict user access to newsgroups, letting users read postings but not add their own, or prevent certain users from reading certain newsgroups.
We believe EServ is one of the more noteworthy proxy servers on the market, as it offers a wide range of services that help small-to-midsize enterprises connect to the Internet in an efficient manner.
Pros: Provides a wide variety of services 7 Access tools are good 7 Easy
to set up and administer 7 Allows Web-based administration 7 Works well
with dial-up connections
Cons: Proxy tools are somewhat limited 7 Web server is functional, not flashy 7 No Unix version
New in v2.93: Support for cascading proxy with authorization on the parent proxy; various minor bugs fixed, including buffer that
overflows in FTPd and SMTPd; correct wildcards support in the aliases and spammers lists;
new versions of Eserv agents
Upgrade Meter: 2
New in v2.96:
Fixed bug in ftp-proxy listings;
TossSpool.bat now runs with cmd.exe under WinNT and command.com under Win9x;
Eserv replies to 'ehlo' command as it expected by new sendmail (to prevent autoconversion from plain text to base64);
fixed bug in FTP server;
fixed bug with Content-Encoding in cache;
fixed bug in InterpretHtml;
small memory leak in http-proxy fixed;
reduced timeout for the closesocket function (to force it fast close)
Upgrade Meter: 3
Version Reviewed: 2.80
Reviewed by: Kevin Reichard
Last Updated: 7/31/01
Date of Original Review: 12/29/99