Solved

smtp - can use any other port other than 25?

Posted on 2011-02-16
6
1,106 Views
Last Modified: 2012-05-11
can smtp use any other port for outgoing mail? how does that get configured or checked?

thanks
0
Comment
Question by:anushahanna
  • 3
  • 2
6 Comments
 
LVL 2

Accepted Solution

by:
Chewe Chileshe earned 167 total points
ID: 34908743
you can use any available port you like, as long as the sever recieving the connections is also configured to recieve smtp on the same port. Thats easy to do when using a relay server, however internet mail works on port 25 as a standard for smtp.

The configuration is dependent on what system you are using.
0
 
LVL 6

Author Comment

by:anushahanna
ID: 34909393
how can we find what port is being used in relay server situation.

port 25 is for the exchange server or the client which uses the exchange server connection to send an email?
0
 
LVL 2

Assisted Solution

by:jbordelon
jbordelon earned 333 total points
ID: 34916967
Port 25 is the open port that server listen for connection. The client should initiate tcp connection on port 25 and then negotiate a high port for return communication. In a Micosoft client like Outlook Express, you configure the SMTP port in the tools menu, accounts, properties, Advanced Options tab, and changing Outgoing Mail (SMTP) value.
You could change the server listen port by different methods depending the operating system, but you couldn't use ports that the server use for other purposes in the same IP address, by example if you use port 80 for SMTP, you cannot run a web server at this port with same IP. Microsoft IIS let you set the port that SMTP server use opening MMC, Internet Information Server, Properties, General Tab and pressing Advanced button. You could use more than one IP addresses in your server, one for SMTP at any port, and other IP for other services.
0
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

 
LVL 6

Author Comment

by:anushahanna
ID: 34935831
>>then negotiate a high port for return communication.

why high port? 24 will work just fine, too, right? what is the reason for the 'high'
0
 
LVL 2

Assisted Solution

by:jbordelon
jbordelon earned 333 total points
ID: 34937810
TCP/IP protocol use source and destination ports. http://en.wikipedia.org/wiki/Transmission_Control_Protocol
When a connection is stablished, two ports are used. One of this ports is defaulted to a service (Well-known ports: 0–1023 http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers ), for example 80 to http, 25 smtp, 21 ftp, 53 dns, etc. Otherwise you wouldn't know at wich port initiate a connection for a protocol or service. The return port could be any unused port in the range 1024-65535 and is called Ephemeral port: http://en.wikipedia.org/wiki/Ephemeral_ports
0
 
LVL 6

Author Comment

by:anushahanna
ID: 34985854
thanks.
0

Featured Post

Use Case: Protecting a Hybrid Cloud Infrastructure

Microsoft Azure is rapidly becoming the norm in dynamic IT environments. This document describes the challenges that organizations face when protecting data in a hybrid cloud IT environment and presents a use case to demonstrate how Acronis Backup protects all data.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Granting full access permission allows users to access mailboxes present in their database. By giving full access permission one can open and read the content of any mailbox but cannot send emails from that mailbox.
Marketers need statistics and metrics like everybody else needs oxygen. In this article we explain how to enable marketing campaign statistics for Microsoft Exchange mail.
To show how to generate a certificate request in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.:  First we need to log into the Exchange Admin Center. Navigate to the Servers >> Certificates…
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…

829 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question