[PLUG] SMTP communications question

[Rich Shepard]

   I understand that when an e-mail message is sent the client MTA initiates
communications with the receiving/relaying server MTA with a HELO or EHLO
command. The recipient MTA is identified by its DNS MX record. Both
HELO/EHLO and MX have a host name prefixed to the domain name.

   Does it matter if the sending MTA host name differs from the PTR host
name? The Frontier DNS tech told me that the PTR host name needed to match
the DNS A record for the sending host (which is mail.)

   My PTR and DNS A records have been set to mail.appl-ecosys.com. When an
outbound message is queued by the recipient MTA's greylisting process I can
see in the postfix queue that the HELO host is salmo.appl-ecosys.com. I
think that the MUA (alpine) adds the host name, but I'm not sure of this.

Rich