Need a change in smtp port!

Discussion in 'Installation/Configuration' started by burice, Feb 29, 2016.

  1. burice

    burice New Member

    Dear Guys, Here I'm facing an odd problem with my ISP!
    My server is configed based on https://www.howtoforge.com/perfect-server-debian-wheezy-apache2-bind-dovecot-ispconfig-3 and everything seems ok.
    but now a days I have a big problem with my isp! the have set the load limit of 128000 packets threshold on port 25 and when the traffic passes this borderline it automatically triggers their security system and announces you as a SPAMMER! and the system automatically routes your IP to NULL!
    You see? only 10 emails in 5 minute is enough for suspending your IP!
    I discussed the matter with their tech support and the told me that I have to send all of my email traffic to other port.
    I have added port 9090 in my postfix mater.cf file without deleting the previous config on port 25 because the IMAP service needs the port 25 and if I block it I wont receive any emails :(
    despite of setting my email clients to use port 9090 it seems that there is enough traffic on port 25 from somewhere i don know!
    Here I am stacked! If I block port 25 my receiving will be blocked and if i don't do that I still have traffic on port 25
    Is there anyway to change the configuration of the server that no to use port 25 in anyway and block it in my firewall?
    if no, is there any way to make ISPCOnfig use other port than 25 for sending copy of emails because It is the only app that I cant tell to use an exact port
    thanx
     
  2. till

    till Super Moderator Staff Member ISPConfig Developer

    No, as all external mail servers will try to connect to your server on port 25 to deliver emails, they can't know your custom port. So your problem is not ISPConfig related, mailsystems that shall be able to receive email need port 25., no matter whcih mailerver or controlpanel software you use.

    get a small vserver in a dataceter and host your mailserver there.
     
  3. tal56

    tal56 Member

    Till I'm curious on this as well. I have a system that only needs to send email via php scripts, but my hosting company has blocked port 25. Is there any way for me to continue to send emails even if my port 25 is blocked? I don't need to receive emails on this system, just send. Also I would prefer not to use a external mail relay, maybe just send using a different port. Thanks
     
  4. till

    till Super Moderator Staff Member ISPConfig Developer

    Mail sending should be possible if they block just port 25 incoming and not outgoing. If they blocked both directions, then you have to use a mail relay.
     
  5. tal56

    tal56 Member

    Nah they blocked both incoming and outgoing.. In the middle of my service agreement too, really upset over this and after I complained they want to charge me $3/month extra for an addon to unblock it now. Definitely avoid using ChicagoVPS if you are looking for a vps.
     
  6. burice

    burice New Member

    Dear till
    I discussed this matter with a friend and he told me to :
    1- set a different port for smtp like 2525
    2- forward the incoming traffic from 25 to 2525 with iptables
    3- drop all outgoing traffic of port 25 in iptables

    does it make sense and do you think this is possible?
    thanx
     
  7. florian030

    florian030 ISPConfig Developer ISPConfig Developer

    You hosting company blocks port 25. you can not redirect any traffic on port25 as your server will never see this traffic.
     
  8. burice

    burice New Member

    no it doesnt. the port 25 is open but totally monitored and if the traffic load rises, specially outgoing traffics, they suspend my IP.
     
  9. florian030

    florian030 ISPConfig Developer ISPConfig Developer

    you can not use a different port to connect to remota mtas.
     
  10. burice

    burice New Member

    how?
    As I'm a newbe would you please make it as simple as possible for me and give more descriptions?
    Thanx
     
  11. florian030

    florian030 ISPConfig Developer ISPConfig Developer

    See Post #2 - you must use port 25 to send and receive mails.it makes no sence to re-route traffic comming from port 25. per the additional 3$/month or a get a different server without blocks from the hosting company.
     
  12. burice

    burice New Member

    Dear florian, that is not me! that's another user interfering my post!
    My case is different! my isp doesn't block port 25 and doesn't want any additional fee! the port 25 is open for me but sending only 10 emails or more triggers their alarm of over threshold on port 25 and they block my IP! they told me to use different port because this alarm only works on port 25 and no other port! that's what they exactly told me to do but I dont know how! would you please guide through this path. they want me to switch my email port!
     
  13. Jesse Norell

    Jesse Norell Active Member

    burice, sounds like you have a pretty lightweight hosting setup, probably intended for hosting a single, small website, not running a webhosting server. As they told you to send on a different port, and port 25 is clearly required for smtp delivery at large, do they have a mail server they allow you to relay through? If so, just send everything there (using port 587 maybe) and see how it works. Other options are to relay your mail through an external mail service, or make a network-level tunnel to an external host (eg. vpn, ssh, stunnel, etc.). And if your incoming mail trips that same 10 messages limit, your options are basically the same - have mail delivered to some other server/service and send to you on an alternate port, or over a tunnel.

    You might see what other hosting plans/arrangements your ISP has. They might be able to open your server/address up more, or move your mail server to a data center; or you may want to consider the costs of a VPS somewhere (compared to a mail filtering service which might be required in your current setup).
     

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