Re: E-mail problem


"Robert Bonomi" <bonomi@xxxxxxxxxxxxxxxxxxxx> wrote in message news:_uudnVkAVbKKgd7VnZ2dnUVZ_v3inZ2d@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <6agff2F37cbq4U1@xxxxxxxxxxxxxxxxxx>,
Owen McKenzie <jomckenzie@xxxxxxxxxxxx> wrote:


Thanks Frank, the change to 587 works.

Now I wonder why 25 worked up until now & then stopped working. Anybody else
useing Escapees for their mail server?

Port 25 is the 'classical' port for mailservers to talk to each other on.
Unfortunately, there is no authentication or other security built into
the standard protocol.

Port 25 is the classic port for POP3 mail servers. The servers that receive mail. The port allows for anonymous authentication. There is a service account on the server just for this purpose.


In the past, port 25 was open to 'everybody', on every mail server, to
originate mail to anywhere.

Port 25 can still be open to everyone, if you want it to be.


Spammers took to taking control of unprotected PCs, installing mail-sending
software on them that talked _directly_ to other mail-servers (bypassing the
local ISP's mailserver where the spamming might be detected).

As a result, many providers have been implementing a block of port 25
from all consumer machines to anything other than _that_ provider's
mail-server. Basically, the only 'port 25' one can reach as a 'customer'
inside of such a network is the mail-server of the network operator.

You may have changed where you were getting your connectivity through,
or your provider may have just gotten around to installing port 25
blocking in your area.

More liekly, port 25 is still available. It's just not being used to access the incoming mail server. When the ISP requires secure password authentication, rather than clear text authentication, to it's service account, it must use the new port assigned for secure password authentication. Port 25 is still being used for anonymous access, but not for users to receive their mail.

In reality, receiving mail is a non-secure issue in regards to SPAMMERS using other people's mail servers. The Spammers want access to your SMTP or IMAP servers.


This is why it 'was working', and has now 'stopped working'.

Port 587 is the 'new standard' port for submitting mail to a mailserver
for transmission, and what _everybody_ *SHOULD*(!!!) use.

It's not the new standard port for submitting mail. It is the standard port for secure passwoird authentication, and it is not new.

It has reasonable
authentication and verification security features, features that were
'built in from the time the protocol was defined.

It was _designed_ to be used when you are 'away' from the network where the
mailserver you're using lives. That's why there is the username/password
authentication requirement built in to it. :)

It is designed to be used when you are outsdide the firewall. The firewall is the part that manages the ports. A LAN might be inside a firewall and users would never be required to use a port to access the server. My client is inside my firewall, yet I still access my mail server through the WAN and therefore have to use a port to get to my mail server. Sitting in my office or sitting in an airport in Atlanta Georgia, I still access my mail server the same way...through a port on my firewall.


Your mail client handles supplying that username/password _automatically_
when it sees the 'demand' for it from the mailserver -- thus you don't
"see" anything different, even though there are significantly different
things going 'under the covers'.

You _could_ have used port 587 starting a long time ago. There just wasn't
any "need" to, until port 25 stopped working for you.

.

Relevant Pages

  • RE: strange traffic on UDP port 53
    ... After deploying a new mail server/internet gateway (behind a firewall) I ... replying to DNS queries which had been forwarded to it by our ISPs' ... again on the next available port. ... The destination IP is our mail server (not ...
    (Incidents)
  • Port 25 closing?
    ... connections to our mail server via port 25. ... port 25 (it can still RECEIVE e-mail since that goes over secure IMAP ... I can log onto the firewall, ...
    (Fedora)
  • Re: Port 25 closing?
    ... > connections to our mail server via port 25. ... I can log onto the firewall, ... > after installing SP2. ...
    (Fedora)
  • RE: strange traffic on UDP port 53
    ... Replies to DNS queries should be coming FROM port 53, ... > found a similar problem with packets being stopped by our firewall. ... The destination IP is our mail server (not ...
    (Incidents)
  • Re: Port 25 closing?
    ... > connections to our mail server via port 25. ... I can log onto the firewall, ...
    (Fedora)