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exim - port 25 and 26

Discussion in 'General Discussion' started by thehawk, Apr 29, 2004.

  1. thehawk

    thehawk Registered

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    I have one quick question and I just want to be sure of that I have the right information. The question is can you run exim on port 25 and port 26 at the same time?

    I am getting conflicting answers on this, but from what I have read, I can do this in the Service Manager.

    Thanks,
    Jim
     
  2. chirpy

    chirpy Well-Known Member

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    Yes, you can and Yes that's where you enable it.

    You have to have exim running on port 25 otherwise you won't be able to receive any email, as all other MTA's use that port.

    You can run exim on port 26 as well, so that users who have ISP's that block outgoing port 25 can still send email through your server. They have to modify their email client to use port 26, instead of port 25 (clearly).

    One more thing, if you have a firewall installed, don't forget to open port 26 ;)
     
  3. thehawk

    thehawk Registered

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    Thank you for the response. I thought that was correct, but I wanted to confrim this before going back to the server tech and telling him he was wrong.
     
  4. anand

    anand Well-Known Member

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    chirpy any ideas on if running exim on another port makes any considerable changes on the memory and cpu utilisation of exim ? I was just wondering on this. Probably you could shed some light on this for me.
     
  5. chirpy

    chirpy Well-Known Member

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    Since you're effectively shifting the load from one service to another, I cannot see that it would have much impact.

    In fact, if you run exim with MailScanner, you're probably already running 3 exim services anyway:

    1. incoming
    2. outgoing
    3. incoming over SSL

    I tend to disable the incoming over SSL as none of our customers use it (comment out the line with 465 on it in /etc/init.d/exim).

    I don't think that one more will make much if any difference.
     
  6. anand

    anand Well-Known Member

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    Shifting load ? We still have people using port 25 for sending mails. The second copy of exim is only for people who have their isp's block port 25.

    What do you say then, still no performance differences ?
     
  7. palash

    palash Member

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    well, he means, the user who use port 26 is a user who cant send via port 25. so no difference in load as he will not send mail via 25.
    hope it's clear.
     
  8. chirpy

    chirpy Well-Known Member

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    Yes, that's exactly what I meant :)

    I don't see that it will make much, if any, impact at all.
     
  9. anand

    anand Well-Known Member

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    thx for the replies.
     
  10. shacker23

    shacker23 Well-Known Member

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    Although port 587 is the official alternate port for SMTP auth and (in my testing) is not blocked by any of the major ISPs, so it's not clear why cPanel defaults to port 26 for the alternate SMTP port rather than 587.

    http://www.chebucto.ns.ca/~rakerman/port-table.html
    (or google "port 587")
     
  11. internetfab

    internetfab Well-Known Member
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    Got a question - when a client turns on SSL on port 25 he can send with no problem.
    If his ISP blocks port 25 and he tries using SSL over port 26 then he cant connect at all.

    Set it just like the client and confirmed the error.

    What am I missing here?
     
  12. chirpy

    chirpy Well-Known Member

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    That because for SSMTP they'll likely need to use port 465.
     
  13. internetfab

    internetfab Well-Known Member
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    I must be missing something here..
    Settings in outlook express:
    smtp port 25
    use SSL: yes
    Works great!

    next try:
    smtp port 26
    use SSL: yes
    No connection

    last try:
    smtp port 26
    use SSL: no
    Works great as well.

    Yeah I thought it would go through port 465 as well - but then changing the smtp port to 26 should have no impact I guess? But it does..

    Anyone able to explain this?

    Oh yeah and if I try with port 465 as smtp port it doesnt connect.
     
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