On 12/02/03 at 09:01, Chris Wagner wrote: > A couple of questions. > > First, what is the HELO command and who is it issued by, the sending or > receiving server, or both?
HELO (or EHLO) is issued by the sending MTA and is usually the first command issued after a connection is established. It's essentially the sending MTA introducing itself to the receiver and the command's argument is supposed to be (but isn't always) the sending MTA's host name. The HELO command should look something like: HELO mail.senders.domain > Secondly, what does this look like to you all? > > 09:06:13 3 SMTP-099(nekatech.net) Failed to get IP addresses. Error Code=-3170 > 09:06:13 3 SMTP-099(nekatech.net) No relay address is accessable. Error > Code=-3170 > 09:06:13 3 SMTP [S.0000305454] dequeueing > 09:06:13 1 SYSTEM(SMTP) [S.0000305454] failed on (nekatech.net)santes. Error > Code=-15001 > 09:06:13 1 SYSTEM(SMTP) [S.0000305454] failed on (nekatech.net)tball. Error > Code=-15001 SIMS is trying to send a message to two addresses (santes and tball) at nekatech.net, but can't find an MX to send to. This is a DNS problem. (An MX query from my machine here returns ex-neka.nekatech.net. which, in turn, resolves to 63.168.156.20) > I just want to make sure that I understand how SIMS works. > > So when you send a message through a SIMS box, it checks to make sure > that: > > 1. The sender is in the client hosts list; Yes, but only if 'Relay for Clients Only' is checked and only if the message is to be relayed to some other MTA rather than delivered to a local account. Note that the 'sender' here is the IP address of the machine that has connected to SIMS. > 2. The sender has an active account on the SIMS box; No. Client hosts and local user accounts are two different things. If 'Advertise AUTH Capability' is enabled, the sender can use SMTP AUTH to authenticate itself as a valid user and override the 'Relay for Clients Only' check, but SIMS doesn't look at the sender's e-mail address other than to verify that its the domain part is an existing domain name (if 'Verify Return-Paths' is checked). > 3. The SIMS box can issue a greeting to the recipient's mail server; In a general sense, yes. As with any other command it sends in an SMTP session, if SIMS' HELO/EHLO gets a response from the remote MTA that indicates some sort of error, SIMS will end the session if appropriate to the error. Just to be clear, the actions in (1) and (3) would take place in different SMTP sessions: the first when the message is sent to SIMS to be relayed (sender connects to SIMS) and the second when SIMS relays the message to its recipient (SIMS connects to recipient's MTA). In the first, SIMS is the receiver; in the second, SIMS is the sender. > I know there is more to it, but if anyone can point me to an RFC to > read the specific commands, I'd appreciate it. RFC 821 (<http://www.faqs.org/rfcs/rfc821.html>) defines the SMTP protocol. There are more recent RFC's that modify and extend it, but 821 establishes the basics. -- Christopher Bort | [EMAIL PROTECTED] Webmaster, Global Homes | [EMAIL PROTECTED] <http://www.globalhomes.com/> ############################################################# This message is sent to you because you are subscribed to the mailing list <[EMAIL PROTECTED]>. To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]> Send administrative queries to <[EMAIL PROTECTED]>
