Consequences of using non-traditional SMTP ports

I'm at an educational institution, and I'm trying to set up a server (Xserve with Mac OS X 10.5.4 Server) within the institution firewall. However, the traditional SMTP (25,587) and IMAP (143,993) ports are blocked so I can't set my mail server to use any of them. The institution has agreed to open up some other ports (22,115,623). Are there any consequences to setting up our mail server using one of these ports?

Could you use port forwarding? sure, although that's overkill if you can put a machine up on the outside of the firewall - just setup a mail server on the outside that knows to forward mail to a port number that the network admins will allow in.
Set your DNS so that your domain's mail goes to the machine on the outside. This machine accepts the mail and forwards it to whatever port number you define on your internal machine. It adds an extra hop in the mail loop but it's entirely feasible, e.g.:
Remote_domain -> outside_machine:25 -> firewall -> inside_machine:623
No remote user needs to know about your inside machine running on a different port number since they only need to talk to the outside_machine that's listening on the standard port.
Now, should you do this? I can't say but I'm sure it's going to fall into the realm of network abuse and the network admins might not appreciate it. That's your call.

Similar Messages

Mailserver using non-standard smtp port

how do i set SMTP to accept connections on a non-standard port (i.e. 2525 or something)?
i'm running a mail server and my residential isp (comcast) after ten years of peaceful coexistence decided that they need to block port 25. so i am setting up a commercial store/forward mail relay service. all i need to do is set up my snow leopard server to accept incoming connections on a port other than 25. sounds easy. it is mentioned in the docs thusly:
"By default SMTP is enabled on port 25. If port 25 is blocked in your environment,
you need to change the port SMTP uses."
... but that's all i can find. specifically, it doesn't say exactly how to change the port.
any help appreciated.

following up to my own post. hoping this info may be useful for others who face the same issue who are running a server and then having email ports blocked by their ISP's.
i worked around this by signing up for a mail relay service (i use the one provided by dnydns.com). they forward incoming mail for my domain over a nonstandard port.
since i never received an answer to my question about how to make SnowLeopardServer email server accept SMTP connections on other ports, i simply used port mapping in my router (Airport Extreme) to redirect this port (i used 2525) on my WAN address to port 25 on my server - an acceptable workaround.
i also did the same port redirection for the other "standard alternative" smtp ports, 465 and 587.
since my ISP blocks port 25 in both directions, i also needed to find a work-around for outgoing mail as well. previously, my mail server simply forwarded to my ISP's smtp server (using the default port 25). here the Server Admin interface worked but with one "trick": under Mail>Settings>General, i left the box for "Relay outgoing mail through host:" checked, and in the field there i put "[smtp.myispdomain.net]:587" (that is with square brackets, and a colon, but no double-quotes - and of course, use your own smtp server's domain name). afaik this is not documented anywhere in the apple-provided docs, but i found the corresponding docs for postfix, and reverse-engineered it.
so now i can read (via IMAP) and send (via SMTP) mail from my home server, both when i am on my LAN and when i am accessing remotely, and effectively work around the bi-directional block of port 25 imposed by my ISP.
i'd still like to know if there is a method of configuring smtp to accept connections on ports other than 25. i can see how to do it by editing /etc/postfix/master.cf, but afaik that file gets overwritten by Server Admin...

How To Configure non-standard SMTP port

My ISP has blocked port 25. I have a service that will deliver mail to the port of my choosing. How do I configure Leopard Server to listen on a non-standard SMTP port? 2525 for example.
Also, I assume all I have to do on my Airport Express is set up NAT to rake external port 2525 and point it to the private address of my email server on port 2525. Is this correct?
Thanks,
-ernie

Assuming such is offered, look to acquire a business-class ISP service level, and move on to the next issue? The business-class services typically provide static IP address(es), opens up server ports, and sets up DNS and ISP-side server connections for your hosts. And you can call your ISP or other assistance when your network craters; non-standard connections are (as you've found) harder to support.
One subtlety here: in a number of cases, simply having a business-class service means you're supported by a different group within (larger) ISPs. This can be a significant advantage at times, given that the scripts and tools and such that are available for the business group will be rather more targeted than the scripts that are available for the residential services group at the ISP.
There are a number of folks that have sought and have tried this (try a few Google searches for SMTP and non-standard port), and it mostly works. But it is fragile, and tends to be derailed when something goes weird, or when the ISP spots and shapes or blocks the server traffic.
Also check your ISP's terms of service here, lest your network pipe be subject to summary disconnection.
The other option is to VPN or tunnel into to a co-lo or dedicated server or a virtual hosting service; to run your servers or virtual servers somewhere without firewalls blocking the standard ports.

Alert emails to a non standard SMTP port

Is it possible to configure LiveCycle ES 8.2 to send its alert emails to an SMTP server on a non standard port? In the AdminUI there is a field for the server but not for the port.
Thanks,

Hi Jon
Sorry, I thought we were talking about Task Notifications not Administrator Notifications.
Changing the port in the Email Notifications process will work for Task Notifications.
Administrator Notifications use the Java mail default, which is port 25 unless otherwise specified on your system.
Are you using the JBoss Turnkey?
if so, you can try this:
1. Navigate to C:\Adobe\LiveCycle8.2\jboss\server\all\deploy
2. Locate the properties-service.xml file.
3. uncomment the following block and set the property as follows:
    
    <attribute name="Properties">
          smtp.mail.port =<your port #>
    </attribute>
4. You don't need to restart JBoss.
The only downside is that this is now the smtp port for that server and any other apps on that server.
If you can live with that, it's an easy workaround.
Diana

Sending email using IMAP through SMTP Port 587

Hi,
I have been sending Mail Merged email to people in organizations that I am active in, using IMAP embedded in StarOffice 5.2 (on Windows 98 Second Edition). This worked fine until a few weeks ago when I received an error message stating that AOL, as part of their anti-spam efforts, was no longer accepting third-party emails on default port 25. All third-party email must now use port 587. I looked in the IMAP dialog and in the Tools -> Options dialog, but did not see any place to change the SMTP port. The AOL error message information page had instructions for changing the port in other applications (Outlook, Eudora, etc.), but not for StarOffice. So, I have some questions:
1.Is it possible to change the port in StarOffice 5.2?
2.If not, how does StarOffice 8 send Mail Merged email? Does it use IMAP, and if so, can the port be changed?
3.Also, I like the integrated configuration in StarOffice 5.2, where database fields can be directly accessed in the Insert -> Fields -> Other dialog. In looking at the Mail Merge section in "SO8_What's New.pdf", it appears that Mail Merge in StarOffice 8 is restricted to predefined fields. Could I still access fields from my existing databases?
These is a lot of questions, but right now I am blocked from sending Mail Merged emails which is imparing communications with volunteers who are running educational programs. I appreciate any and all help that anyone can provide.

Please try this out!!!!!!!!!
You can send emails using Outlook also. You can send email over Microsoft Exchange with this object (or another email server, using IMAP/POP).
Sub SendMailOutlook(aTo, Subject, TextBody, aFrom)
'Create an Outlook object
Dim Outlook 'As New Outlook.Application
Set Outlook = CreateObject("Outlook.Application")
'Create e new message
Dim Message 'As Outlook.MailItem
Set Message = Outlook.CreateItem(olMailItem)
With Message
'You can display the message To debug And see state
'.Display
.Subject = Subject
.Body = TextBody
'Set destination email address
.Recipients.Add (aTo)
'Set sender address If specified.
Const olOriginator = 0
If Len(aFrom) > 0 Then .Recipients.Add(aFrom).Type = olOriginator
'Send the message
.Send
End With
End Sub

Using non-standard sshd port after 10.8 upgrade

After spending hours tracking down this solution as a result of losing my ssh settings after the upgrade to Mountain Lion, I thought it might be useful to post the steps taken to restore the configuration I used with Snow Leopard.
Changing the sshd default listening port
Disclaimer: This tutorial is specific to Mountain Lion (OS X 10.8). I was able to accomplish this using Snow Leopard (OS X 10.6) in fewer steps, but upgrading required this more involved solution.
Steps:
1.) You must first enable the root user account in order to change the relevant files. This can be done from the terminal, or by going to System Preferences --> Users & Groups. Once there, click on 'Login Options' at the bottom of the Current User list, and 'Join' where it says 'Network Account Server'.
This will bring up a smaller window. Click on 'Open Directory Utility' at the bottom. You will be prompted for your admin password. Now go to the 'Edit' tab at the top of the screen and toggle down to 'Enable Root User'. You will be prompted to enter your admin password twice.
2.) Log out of your regular user account. At the log in screen you will now see an additional entry for 'other'. Click on that and log in with the username 'root' and your admin password. If are inexperienced as a root-level user, be careful as you can cause problems to your system can be difficult to undo.
Once in your root account, the first step is to create a new 'service definition' in the etc/services file. Open the file with text editor of choice and scroll to the current entry for sshd listening port, which will look like this:
ssh    22/udp    # SSH Remote Login Protocol
ssh    22/tcp     # SSH Remote Login Protocol
Overwrite the '22' with the port number you would like sshd to listen on:
ssh    12345/udp   # SSH Remote Login Protocol
ssh    12345/tcp    # SSH Remote Login Protocol
*12345 being our hypothetical, non-standard port.
It is important to note that the new port number will not take by simply adding a new uncommented line to the file (I tried), unless of course you comment the original ssh entries. Easiest way is just to overwrite what is there already. Save changes.
3.) You now need to edit the ssh.plist file, which is located at /System/Library/LaunchDaemons/ssh.plist. A word to those familiar with Linux/BSD environments: changing the default port in the sshd_config file, which exists in OS X, does NOT change the listening port. Simply changing the default port, saving the config file, and restarting the server (the sensible way) won't work. The OS X sshd server (openssh) is configured to get launch instructions from the ssh.plist file, as opposed to sshd_config. If you are more interested in this aspect of OS X, read up on LaunchDaemons (e.g. launchd).
Before altering the ssh.plist file, you should save a backup copy in case of mistakes, or if you need to revert back to it in the future. Name your backup file something like original.ssh.plist, etc.
In the ssh.plist file, locate the SocksServiceName entry and change it from the default:
<key>SockServiceName</key>
<string>ssh</string>
To the following:
<key>SockServiceName</key>
<string>$alternate port number</string>
In our example from above this value would be 12345.
4.) Save your changes, and exit ssh.plist. You now need to move the backup file you created (original.ssh.plist) out of the System/Library/LaunchDaemons path.
The updated sshd port will not take until you have only one ssh.plist file in the LaunchDaemons directory - this has to do with how launchd is configured to load files which is outside the scope of the current discussion. (*If you've found a way around this, please share.)
5.) Restart the sshd server. Easiest way to accomplish this is going to System Preferences --> Sharing and clicking off 'Remote Login', then clicking back on it.
6.) Test the configuration by logging into the machine running the sshd server from another host using:
ssh username@ipaddress -p 12345
There are a few good tutorials out there that capture some of these steps, but many are dated and/or incomplete. If you are running a standard setup of OS X 10.8, this should work for you.
Of course, don't be fooled into thinking that changing the default listening port from the ubiquitously-probed 22 equates to actual security. At best, it will cut down on the number of dubious connection attempts and probing.

Hi all, above helped me change the sshd port number, thank you very much.
Just upgraded to OS X 10.9.3 on my macbook pro.
My findings were:
Step 1(become a root user or sudo)
Step 2 (/etc/services)
This may not be required unless you want ssh to work without the "-p XXXX" option to connect to other ssh hosts. I favor such as "ssh -p 2222 user@hostname" just to be sure I know what I am doing and also to leave ssh known port as its default "22".
Step 3 (/System/Library/LaunchDaemons/ssh.plist)
This is required if you want to change the sshd port number, I changed both "ssh" to "2222" in this file.
Step 4 (launchctl)
Below is a must as I understood:
launchctl unload /System/Library/LaunchDaemons/ssh.plist
launchctl load /System/Library/LaunchDaemons/ssh.plist
it should be already working with the new port number.
You can "ssh -p 2222 user@localhost" in the console terminal and see if its working.
Since I am no expert on MacOS X, and it is a macbook pro that I am using, I also rebooted the system and changes were reflected permanantly.
Thank you guys!

Using non-BT 3 port Powerline adapters

Is it possible to replace either just the Powerline adapter at the BT Vision end, or at both ends, with a 3-port one such as this and have it work?
I've recently bought a new Smart TV as well as a Freesat box that is also internet enabled and I'm wondering if I can easily connect all three without resorting to getting an ethernet hub or switch and having to find somewhere for it to sit!
Thanks.

An Ethernet switch is very small, is a lot cheaper (£8) and more reliable than adding more adapters.
There are some useful help pages here, for BT Broadband customers only, on my personal website.
BT Broadband customers - help with broadband, WiFi, networking, e-mail and phones.

Change port used to send SMTP e-mail

I am trying to send e-mail notifications using a .vi. My company has blocked SMTP port 25 to prevent SPAM. My IT has told me that there is another port I can use to send e-mail. It is possible for me to change, IN LABVIEW, the port used to send e-mail?
Thank you.

Without modifying NI's SMTP library the answer is no. The port they use (25, standard SMTP port) is hardcoded in their library.
Message Edited by Mark Yedinak on 09-15-2009 10:31 AM
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot

SMTP port number resets to 25 after every reboot

Because of our ISP, we have to use a non-standard SMTP port number to send via our mail server. This works just fine when I change the SMTP port in the Mail program. However, every time I reboot my MacBook, the port is reset back to 25, and I have to manually go in and change the port number again. This is of course really annoying. Does anyone have a fix for this problem, and has anyone else experienced it? Thanks for any help!

No, you wouldn't see any error messages, because as far as the system knows, it is saving those changes. But if the file is corrupt, those changes don't stick when you quit Mail, so it reverts to the default.
Since you have a POP account, quit Mail, remove the com.apple.mail.plist file from Home/Library/Preferences, then restart Mail and setup the account(s) again and Mail will find and "import" the existing email folders. Then setup your SMTP port preferences again, quit Mail and restart to see if they stick. If they do, you can delete the old com.apple.mail.plist file.

HT4759 I need to set up icloud mail keep getting message about non traditional roman letters?

I continually get a message in read telling me I can't use non-traditional Roman letters in the e-mail account.

Is your email address using strange letters (non Roman)? You might try creating an alias email address using normal letters. See link...
http://support.apple.com/kb/PH2622
Admitedly I may not have this right. There was a post a week or so ago regarding this problem. I just don't recall whether it was the primary email address of the icloud account that was the problem or something else. At any rate, look at this link, it might help.
http://support.apple.com/kb/HT5621?viewlocale=en_US

E61 SMTP Port problem

I have a E61 since a few days. Unfortunately I cannot configure the SMTP port. Here in the office the port is 2525, but obviously it is only possible to enter 3-digit-numbers in the profile.
Is there a workaround? The confuguration tool is of no use as well...

Hi,
the only way is to use change the smtp port to 3 digits.I don't know but it can be possible to add a second port number without to remove the port with 3 digits.
I hope it will be help.I have read in the discussion the same problem.Thats was the solution provided.
Best regrds,
Cengiz Kuskaya
ckuskaya

Alternate SMTP Port

How do I set up 10.4.6 Server to use a different SMTP port? I would like to set it up to use an alternate port of like 465 since my remote users are getting their port 25 blocked frequently.
Are there different settings for the alternate SMTP port if you are using SSL or not?
Thank you.
1.67GHz 15" PowerBook Aluminum Mac OS X (10.4.6) 2GB RAM, 80GB 5400 RPM HD, SuperDrive

You can uncomment some lines in master.cf as described by UptimeJeff here:
http://discussions.apple.com/thread.jspa?messageID=2222925
This will enable SSL/TLS on port 587, which is referred to as the "Submission" port. I believe it's even a standard. Apple implements the same functionality for their .Mac servers.

How can I see / change the smtp ports in use by FF 12.0 on my WIN2K antique?

My webmail account works, though slowly, when I'm using NetScape 7.1. When I try to use the same program and service with FireFox 12.0, I can receive email, but sending email gets me an error message that's something like "Could not establish an SMTP commection with the server." The service tells me that my outgoing smtp port should be 465 if I'm using SSL, and 25 if I'm not using SSL. Also, if I'm asked about "authentication," it should be "the same as incoming." Where do I find these settings in FF12.0?
I'm asking this question on another computer, not the one I'm having trouble with. My problem child is an IBM Aptiva running Windows 2000 Version 5.0 (Build 2195; Service Pack 4) Copyright 1981-1999 Microsoft Corp. Physical memory available to Windows: 64,824 KB

Gingerbread_Man, you were right on the nose with the answer to the problem. After I installed Simple Mail v. 2.83.2, my webmail began to work with Firefox v. 12.0. My s-l-o-w computer is now a bit faster, as well, though I don't know how that could have had any connection with Simple Mail. Oh, Telga, TechnalXS, the developer, changed versions to 2.84 while I was installing 2.83.2, so I started over and finished up with the new one. What had me going was that every time I tried to print a copy of their web site, Firefox crashed and burned. Had to be that document, because other things print just fine. Anyway, thanks for your help. I'm going to recommend that Santa put you on his "good list!"

How to use non default port 1521 while 11.2.0.1 grid upgrade to 11.2.0.2

Hi Team ,
We are planning 11.2.0.1 Grid infra rolling upgrade to 11.2.0.2 with out any downtime.
But while up gradation due to default scan port 1521 , 11.2.0.1 databases are not able to connect (remote connections)
We are using 1900 port for existing 11.2.0.1 grid infra scan.
While up gradation it is taking default port of 1521 insted of existing port 1900.
Please provide the solution to use non default port while 11.2.0.2 up gradation.
After upgrade the status as below.
grdoratst104:/apps/grid/grdhome:+ASM4> srvctl config scan_listener
SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN3 exists. Port: TCP:1521
Here I was getting TNS:no Listener errors from the client connections.
I have modifyed the scan port then it is working fine.
grdoratst104:/apps/grid/grdhome:+ASM4> srvctl modify scan_listener -p TCP:1800
grdoratst104:/apps/grid/grdhome:+ASM4> srvctl config scan_listener
SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1800
SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1800
SCAN Listener LISTENER_SCAN3 exists. Port: TCP:1800
grdoratst104:/apps/grid/grdhome:+ASM4>
Here the problem is we need to do the grid infra upgrade with out downtime,but due this default port issue clients are not able to connect to the database.
Thanks
Bala
Edited by: user12032334 on May 31, 2011 11:46 AM

Why are you using a non default port? It does not improve security. It makes network management more complex. And causes the type of issues that you are facing now.
So before changing defaults, make sure that your reasons are technically sound. And using port 1900 when 1521 is available, is not technically sound by any means.
As for addressing the problem you have created for yourself by mucking around with port numbers. Use a NAT firewall (on each RAC node) to rewrite packets headers received on port 1900 and send these to the server's port 1521 instead (on the VIP or static IP as required).
This can be fairly easily done using iptables if your o/s is Linux. You need to:
a) create a pre-routing NAT rule
b) create a post-routing NAT rule
c) create a forwarding filter rule for port 1900/tcp
d) create an input filter rule to accept traffic on 1900/tcp

CSS 11501 ftp server setup problem using non-standard port

Dear Expert,
we would like to setup FTP server over CSS where our member sever use non-std-port to open both control/data channel (i.e. 6370 as ctrl and 6369 as data this case.) but seems we only get Passive mode FTP mode work only but not for Active mode FTP case for data channel establishement for server back to client...is there any professional advise can help on this case...? here is our setup info FYI
# sh ver
Version:               sg0820501 (08.20.5.01)
Flash (Locked):        08.10.1.06
Flash (Operational):   08.20.5.01
Type:                  PRIMARY
Licensed Cmd Set(s):   Standard Feature Set
                       Secure Management
CVDM Version:          cvdm-css-1.0_K9
!*************** Global
ftp data-channel-timeout 10
ftp non-standard-ports
!************************** SERVICE **************************
service ftp_ftpgtw
keepalive maxfailure 2
keepalive frequency 15
keepalive retryperiod 2
keepalive type tcp
ip address 192.168.52.170
protocol tcp
keepalive port 6370
port 6370
active
# sh run group drfusegtwftp_grp
!*************************** GROUP ***************************
group gtwftp_grp
vip address 192.168.52.28
add service ftp_ftpgtw
active
content ftp_gtwpkg-ftpgtw
    add service ftp_ftpgtw
    vip address 192.168.52.28
    port 21
    protocol tcp
    application ftp-control
    active

Thanks for your confirmation on no prob found in config level 1st..:P..as to save us a lot of time in isolating problem at this level.
What we can notice is seems the data port connection is fail to open for server back to client....for our general sense..... the flow expected should be:
TCP session A -- Client:1234 --> VIP:21 --> member svr:6370
TCP session B -- Client: 5678 <--> VIP:20 <--> member Svr: 6379 [on demand generated between server/client]
but we can only see session B fail to setup when client side access VIP site on CSS..even we try to put the most standard case as below
TCP session A -- Client:1234 --> VIP:21 --> member svr:21
TCP session B -- Client: 5678 <--> VIP:20 <--> member Svr: 20
we still unable to make the Active mode FTP access work either...hence we got no idea on how CSS handle FTP access when it involve services over multiple tcp ports..
and from CSS xlate view...the problem is we can only see what NAT IP that used in CSS connect to client...but no way to confirm for which port for VIP using outgoing to client. neither it is dropped by CSS..nor it is never setup from VIP to Client side.

Consequences of using non-traditional SMTP ports

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