Re: [Dovecot] change smtp port
On 2012-01-23 11:14 AM, Noel noeld...@gmail.com wrote: If your problem is that your Internet Service Provider is blocking port 25, you can contact them. Some ISPs will unblock port 25 on request, or might even have an online form you can fill out. The OP specifically said that *he* had changed the port from 25 to 587... obviously he doesn't understand how smtp works... -- Best regards, Charles
Re: [Dovecot] change smtp port
On Tue, 24 Jan 2012, Charles Marcus wrote: On 2012-01-23 11:14 AM, Noel noeld...@gmail.com wrote: If your problem is that your Internet Service Provider is blocking port 25, you can contact them. Some ISPs will unblock port 25 on request, or might even have an online form you can fill out. The OP specifically said that *he* had changed the port from 25 to 587... obviously he doesn't understand how smtp works... Most probably he wanted to enable his users to send emails via his mail server using port 587, because some may have blocked access to port 25. Proper solution is to open additionally port 587 and require users to authenticate in order to send mails through the server. If it is too complicated in postfix, admin can simply map port 587 to 25 - most probably that would work well. Best regards, -- Jacek Osiecki jos...@ceti.pl GG:3828944 I don't want something I need. I want something I want.
Re: [Dovecot] change smtp port
On 2012-01-24 6:51 AM, Jacek Osiecki jos...@hybrid.pl wrote: On Tue, 24 Jan 2012, Charles Marcus wrote: On 2012-01-23 11:14 AM, Noel noeld...@gmail.com wrote: If your problem is that your Internet Service Provider is blocking port 25, you can contact them. Some ISPs will unblock port 25 on request, or might even have an online form you can fill out. The OP specifically said that *he* had changed the port from 25 to 587... obviously he doesn't understand how smtp works... Most probably he wanted to enable his users to send emails via his mail server using port 587, because some may have blocked access to port 25. Which obviously means he has not even a basic understanding of how smtp works. Proper solution is to open additionally port 587 and require users to authenticate in order to send mails through the server. If it is too complicated in postfix, Which is precisely why I (and a few others) gave him those instructions... admin can simply map port 587 to 25 - most probably that would work well. Of course it will work... but it is most definitely *not* recommended, and not only that, will totally defeat achieving the goal of using the submission port (because *all* port 587 traffic would be routed to port 25)... I only mentioned that this could be done in answer to someone who said it couldn't... -- Best regards, Charles
Re: [Dovecot] change smtp port
Thanks for reply The problem that ISP for some reason port 25 is not stable and refuse connection for several times so I tried to change port to 587 instead of 25 to keep sending emails. And I though that I can stop using port 25 as it's not always working from ISP -Original Message- From: dovecot-boun...@dovecot.org [mailto:dovecot-boun...@dovecot.org] On Behalf Of Charles Marcus Sent: Tuesday, January 24, 2012 2:19 PM To: dovecot@dovecot.org Subject: Re: [Dovecot] change smtp port On 2012-01-24 6:51 AM, Jacek Osiecki jos...@hybrid.pl wrote: On Tue, 24 Jan 2012, Charles Marcus wrote: On 2012-01-23 11:14 AM, Noel noeld...@gmail.com wrote: If your problem is that your Internet Service Provider is blocking port 25, you can contact them. Some ISPs will unblock port 25 on request, or might even have an online form you can fill out. The OP specifically said that *he* had changed the port from 25 to 587... obviously he doesn't understand how smtp works... Most probably he wanted to enable his users to send emails via his mail server using port 587, because some may have blocked access to port 25. Which obviously means he has not even a basic understanding of how smtp works. Proper solution is to open additionally port 587 and require users to authenticate in order to send mails through the server. If it is too complicated in postfix, Which is precisely why I (and a few others) gave him those instructions... admin can simply map port 587 to 25 - most probably that would work well. Of course it will work... but it is most definitely *not* recommended, and not only that, will totally defeat achieving the goal of using the submission port (because *all* port 587 traffic would be routed to port 25)... I only mentioned that this could be done in answer to someone who said it couldn't... -- Best regards, Charles
Re: [Dovecot] change smtp port
On 1/24/2012 5:23 AM, Charles Marcus wrote: On 2012-01-23 11:14 AM, Noel noeld...@gmail.com wrote: If your problem is that your Internet Service Provider is blocking port 25, you can contact them. Some ISPs will unblock port 25 on request, or might even have an online form you can fill out. The OP specifically said that *he* had changed the port from 25 to 587... ... because port 25 didn't work. obviously he doesn't understand how smtp works... and we can assume he's here to learn, not to get flamed. Anyway, this is OT for dovecot. Over and out. -- Noel Jones
Re: [Dovecot] change smtp port
On 2012-01-24 7:51 AM, Amira Othman a.oth...@cairosource.com wrote: Thanks for reply The problem that ISP for some reason port 25 is not stable and refuse connection for several times so I tried to change port to 587 instead of 25 to keep sending emails. And I though that I can stop using port 25 as it's not always working from ISP As I said, you obviously do not understand how smtp works. This is made obvious by your questions, and failure to understand that port 25 is *the* port for receiving email on the public internet. Period. If your main problem with port 25 is *sending* (relaying outbound) mails, then you will need to take this up with your ISP. If they are unable or unwilling to address the problem, one option would be to setup your system to relay through some other smtp relay service on the internet using port 587 as you apparently read somwehere, but you don't do this by changing the main smtpd daemon to port 587, because as you discovered, you won't be able to receive *any* emails like this. That said, I fail to see any relevance to dovecot in this thread... -- Best regards, Charles
Re: [Dovecot] change smtp port
On 2012-01-24 8:39 AM, Noel noeld...@gmail.com wrote: On 1/24/2012 5:23 AM, Charles Marcus wrote: The OP specifically said that *he* had changed the port from 25 to 587... ... because port 25 didn't work. For *sending*... And his complaint was that changing the port for the main smtpd process caused him to not be able to *receive* email... obviously he doesn't understand how smtp works... and we can assume he's here to learn, not to get flamed. What!? Please point out how simply pointing out the obvious - that someone doesn't understand something - is the same as *flaming* them... Please... Anyway, this is OT for dovecot. Over and out. Agreed on that one... nip/tuck
Re: [Dovecot] change smtp port
On 2012-01-23 14:30, Amira Othman wrote: Hi all I am using postfix 2.8 with dovecot-1.2.17-0_116.el5 on cento 5.7 server . when I changed smtp port from 25 to 587 from postfix configuration my mail server stops to receive emails. I think it sounds strange and I don't understand why this happen any one can help me Regards If this SMTP server is your MX record, then you need to use port 25. Only use the 587 port for authenticated submissions from your own users for outgoing email. -- Message sent via my webmail account.
Re: [Dovecot] change smtp port
* Amira Othman a.oth...@cairosource.com: Hi all I am using postfix 2.8 with dovecot-1.2.17-0_116.el5 on cento 5.7 server . when I changed smtp port from 25 to 587 from postfix configuration my mail server stops to receive emails. That's normal. I think it sounds strange and I don't understand why this happen any one can help me Mail from other systems comes in via port 25. Once you change the port, nobody can send mail to your server. Easy, no? -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: [Dovecot] change smtp port
And there is no way to receive incoming emails not on port 25 ? Hi all I am using postfix 2.8 with dovecot-1.2.17-0_116.el5 on cento 5.7 server . when I changed smtp port from 25 to 587 from postfix configuration my mail server stops to receive emails. That's normal. I think it sounds strange and I don't understand why this happen any one can help me Mail from other systems comes in via port 25. Once you change the port, nobody can send mail to your server. Easy, no? -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
Re: [Dovecot] change smtp port
On 2012-01-23 14:38, Amira Othman wrote: And there is no way to receive incoming emails not on port 25 ? No. http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol
Re: [Dovecot] change smtp port
On 2012-01-23 9:41 AM, Giles Coochey gi...@coochey.net wrote: On 2012-01-23 14:38, Amira Othman wrote: And there is no way to receive incoming emails not on port 25 ? No. http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol Well, not precisely correct... You *could* use a router that does port translation (translates incoming port 25 connections to port 587), but that would be extremely ugly and kludgy and I certainly don't recommend it. Amira - what you need to do is re-enable port 25, and then enable the submission service (port 587) at the same time (just uncomment the relevant lines in master.cf), and require your users to use the submission port for relaying their mail. -- Best regards, Charles
Re: [Dovecot] change smtp port
On 2012-01-23 14:50, Charles Marcus wrote: On 2012-01-23 9:41 AM, Giles Coochey gi...@coochey.net wrote: On 2012-01-23 14:38, Amira Othman wrote: And there is no way to receive incoming emails not on port 25 ? No. http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol Well, not precisely correct... Now true, you can do anything you like internally, but if you want to listen and speak with the rest of the Internet, you should be RFC compliant. RFC821 Connection Establishment The SMTP transmission channel is a TCP connection established between the sender process port U and the receiver process port L. This single full duplex connection is used as the transmission channel. This protocol is assigned the service port 25 (31 octal), that is L=25. RFC531 4.5.4.2. Receiving Strategy The SMTP server SHOULD attempt to keep a pending listen on the SMTP port (specified by IANA as port 25) at all times. This requires the support of multiple incoming TCP connections for SMTP. Some limit MAY be imposed, but servers that cannot handle more than one SMTP transaction at a time are not in conformance with the intent of this specification. As discussed above, when the SMTP server receives mail from a particular host address, it could activate its own SMTP queuing mechanisms to retry any mail pending for that host address.
Re: [Dovecot] change smtp port
On 1/23/2012 8:38 AM, Amira Othman wrote: And there is no way to receive incoming emails not on port 25 ? You can't randomly change the port you receive mail on because external MTAs have no way to find what port you're using. They will *always* use port 25 and nothing else. If your problem is that your Internet Service Provider is blocking port 25, you can contact them. Some ISPs will unblock port 25 on request, or might even have an online form you can fill out. If you can't get help from the ISP, you need a remailer service -- some outside proxy that accepts the mail for you and forwards connections to some different port on your computer. I don't know of any free services that do this; dyndns and others offer this for a fee, sometimes combined with spam/virus filtering. -- Noel Jones
