ISPs and smtp.fnal.gov

Some Internet Service Providers (ISP) and institutions either block outbound traffic on port 25 or have a proxy server configured to relay the connection for you. If your ISP uses one of these methods to restrict access to port 25 then you may have a problem using smtp.fnal.gov from home. This is not a problem with the smtp.fnal.gov service but a restriction that your ISP has put in place in an attempt to limit the spam that originates from their network.

The following ISPs are known to have either blocked port 25 or implemented a proxy gateway:

• AOL
• Earthlink
• AT&T Dialup
• SBC Yahoo

This restriction will normally present itself with an error like this: (Outlook)

Task 'user@fnal.gov - Sending' reported error (0x800CCC7D) : 'Your
outgoing (SMTP) server does not support SSL-secured connections. If
SSL-secured connections have worked in the past, contact your server
administrator or Internet service provider (ISP).'

or (Outlook Express)

The connection to the server has failed. Account:
'imapserverX.fnal.gov', Server: 'smtp.fnal.gov', 
Protocol: SMTP, Port: 25, Secure(SSL): Yes, 
Socket Error: 10060, Error Number: 0x800CCC0E

How do I know if my ISP blocks SMTP?

Unfortunately you may not know until you attempt to send mail using smtp.fnal.gov and it fails. Assuming that other connectivity is ok to services at the lab (IMAP, Web, etc) a couple of simple checks can be done to see if it is related to your ISP.

>nslookup smtp.fnal.gov
Server:  fnsrv0.fnal.gov
Address:  131.225.8.120

Name:    mailgw.fnal.gov
Address:  131.225.111.1
Aliases:  smtp.fnal.gov

>telnet smtp.fnal.gov 25

220 mailgw2.fnal.gov -- Server ESMTP (iPlanet Messaging 
Server 5.2 HotFix 1.21 (built Sep  8 2003))
helo
251 mailgw2.fnal.gov system name not given in HELO command.
quit
221 Closing connection. Good bye.

If the nslookup works but the telnet fails then it is likely that your ISP has decided to block outgoing SMTP connections.

What can I do?

1. Use the VPN
2. Configure your mail client to use SMTP over SSL
3. Contact your ISP. Some, like SBC Yahoo, have a procedure to allow outgoing SMTP