Port 57 vs 587 - Networking

This is a discussion on Port 57 vs 587 - Networking ; At my office: OK (out-going mail): telnet servername 25 OK: telnet servername 110 At my client's office: No: telnet servername 25 OK: telnet servername 110 On advise of the web host, at client office change port 25 to 587: OK: ...

+ Reply to Thread
Results 1 to 4 of 4

Thread: Port 57 vs 587

  1. Port 57 vs 587

    At my office:

    OK (out-going mail): telnet servername 25
    OK: telnet servername 110

    At my client's office:

    No: telnet servername 25
    OK: telnet servername 110

    On advise of the web host, at client office change port 25 to 587:

    OK: telnet servername 587


    Question: Why is this so ?

    Thanks.

  2. Re: Port 57 vs 587

    sb5309@yahoo.com writes:

    > At my office:
    >
    > OK (out-going mail): telnet servername 25
    > OK: telnet servername 110
    >
    > At my client's office:
    >
    > No: telnet servername 25
    > OK: telnet servername 110
    >
    > On advise of the web host, at client office change port 25 to 587:
    >
    > OK: telnet servername 587
    >
    >
    > Question: Why is this so ?


    I work at a web host, we tell people to change to 587
    in cases where their ISP blocks port 25 connections attempting
    to leave their network, i.e. they are trying to stop spammers.


    --
    John
    __________________________________________________ _________________
    John Murtari Software Workshop Inc.
    jmurtari@following domain 315.635-1968(x-211) "TheBook.Com" (TM)
    http://thebook.com/

  3. Re: Port 25 vs 587

    On Wed, 23 Apr 2008 12:40:10 -0400, John Murtari wrote:

    > I work at a web host, we tell people to change to 587 in cases where
    > their ISP blocks port 25 connections attempting to leave their network,
    > i.e. they are trying to stop spammers.


    I don't know the history, but somewhere along the way 587 became the
    standard "email submission" port. The idea is that this is distinct from
    "email transfer", the latter being server-server and the former being
    client-server.

    This permits different rules (or even different softwares!) to be applied
    to the different ports. Incoming traffic on port 25 must be to a domain
    handled by that server, for example, while incoming traffic on port 587
    must be authenticated.

    At least some SMTP servers (ie. sendmail) can be configured to handle
    "local domain or authenticated" on a single port, which is where I suffer
    from a bit of ignorance: I don't know why the desire for different ports
    arose. Perhaps to run different softwares for the different audiences w/
    o wasting IPv4 space?

    - Andrew

  4. Re: Port 57 vs 587

    sb5309@yahoo.com writes:

    > At my office:
    >
    > OK (out-going mail): telnet servername 25
    > OK: telnet servername 110
    >
    > At my client's office:
    >
    > No: telnet servername 25
    > OK: telnet servername 110
    >
    > On advise of the web host, at client office change port 25 to 587:
    >
    > OK: telnet servername 587

    Earthlink ISP advises the same for configuring email clients. All I
    know is that it works.

    --
    Allan

+ Reply to Thread