My mail server vendor will have SPF later this year.
Why do I need ASMTP?
SPF detects two mechanisms used by spammers:
forged sender addresses and forged HELO hostnames.
ASMTP has 10 filters including these two filters provided by SPF
and three filters patented by ESCOM.
Further, ASMTP sender address and HELO filters include other heuristics
in addition to SPF -- these are particularly important until more
domains publish SPF records.
For more information, see ASMTP Overview.
We understand Red Hat is discontinuing support for Red Hat Linux.
How does this affect ASMTP?
Only that ESCOM has had to qualify ASMTP with Red Hat Enterprise Linux.
We now have a single Red Hat ASMTP distribution that will run on
traditional Red Hat Linux and also on Red Hat Enterprise Linux.
We believe most current customers will continue to run ASMTP on
Red Hat Linux (e.g., 7.1) until the hardware fails and they need to
How many users can ASMTP support?
The upper limit for a single ASMTP Appliance is probably on the order of 30,000 users,
depending on the hardware platform and how WebQS is configured.
An ISP customer has a single appliance (800 MHz CPU) supporting 10,000 users,
and the top utility typically shows the CPU over 90% idle.
Larger networks may require faster CPUs, multiprocessor systems,
and more physical memory.
Load sharing is possible by connecting multiple appliances in parallel behind a TCP switch.
For example, a university with 60,000 users has three ASMTP Appliances
NFS mounted for sharing of databases and quarantine files.
The most basic ASMTP configurations should handle
in excess of 100,000 messages per hour and
throughputs of up to 1.5 megabits/second.
What mail programs does ASMTP support?
ASMTP operates at the SMTP level, so it should be compatible
with all Mail Transfer Agents (MTAs) and all user mail client programs.
The only constraints are:
Your mail server must use the IP protocol stack (ASMTP does not support IPX).
Your mail server must use SMTP.
What mail servers does ASMTP work with?
ASMTP is currently being used with the following mail servers:
We have not observed any problems with mail from any particular server.
We believe that ASMTP can receive mail from any SMTP or ESMTP server
currently being produced.
Does ASMTP scan for viruses?
No, but ASMTP can find and quarantine risky attachments such as
.bat, .exe, .lnk, and .vbs
that have traditionally been used to propagate viruses.
You can define the specific file types to be quarantined for your network
and ASMTP will divert them to the quarantine directory instead of the mail server
even if they come from trusted hosts.
Other customers have installed ASMTP in tandem with virus-filtering appliances
such as NAI WebShield.
And one customer has installed ASMTP with sendmail/Sophos,
so that one appliance handles both spam and virus filtering.
Does ESCOM provide on-site hardware maintenance?
No, but the major hardware manufacturers (Dell, Compaq/HP)
provide onsite hardware support.
Is there a way for individual users to review their own quarantined messages?
The Web-based Quarantine Server (WebQS) runs as an extension to an Apache web server
on the ASMTP Appliance.
A user can open up a browser connection (Netscape, IE5, Opera, Lynx) to WebQS,
login, and see a listing of messages as shown below for that user:
WebQS Home Page for email@example.com: Fri Sep 17 15:44:47 2004
Access List | Change Password | Databases | Statistics | OS Commands | Help
Subject (click below to view message)
5.5 cents/min Long Distance
Re: Ticket number 1537
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Reload page with all messages preselected for: Junk Send Neither
Reload page sorted by: Date/Time Subject Sender
The user can select radio buttons to dispose of the message based on the
information in the table, or can click the Subject link to view the message.
Other links permit a user to enable/disable filtering for him or her self,
change the user password, and view or edit the user's individual access list.
How do I keep mail running if I need to repair the ASMTP Appliance?
Should I buy a pre-loaded ASMTP Appliance instead of the ASMTP software distribution?
The main reason for buying an ASMTP Appliance from ESCOM is to avoid
hardware selection and loading an operating system.
The main reasons for installing the ASMTP software on your own hardware are:
(1) You want to run ASMTP on a different platform, e.g., to handle more users;
(2) You can get better hardware discounts if you buy direct from the manufacturer;
(3) You want to do a custom installation of Red Hat Linux; or
(4) You want to install a different Red Hat release.
For example, the license for Red Hat Enterprise Linux prohibits ESCOM
from loading the OS and redistributing it to our customers.