Is it possible to send an email in C# console, without needing and SMTP server?
Edit:
Why do I need another SMTP server? Can not I use my localhost machine as a server..?
Edit:
I just need to send an email from with my domain name, for example abc#mydomain.com
Is that possible? what do I need to do this in my C# program... I do not care about receiving emails, I just care about sending them....
Thanks
You don't have to depend on a local SMTP server if you don't have one. However, you will have to connect to a SMTP server anyway. Here is why.
You must achieve the following steps:
Determine what is the mail exchange servers of a given domain.
Connect to that mail exchange server and deliver your mail.
Those steps are normally done by your local SMTP server. Another advantage of your local SMTP server is that it will handle its queue and continue to try to deliver your email if it fail.
How to determine the MX records of a give domain.
I suggest you to have a look at this answer. Basically, you have to do a query on a DNS server to get the list of MX records of the domain name of the email address you want to send an email to.
How to connect to a mail exchange server
Well the answer will disappoint you. Exactly like you connect to your local SMTP server. Using the TcpClient, you connect to one of the mail exchange server you got at the previous step on port 25 and start the delivering process using the SMTP protocol.
The trick here is that you must handle multiple MX servers. They are usually listed with a preference. If the first one is unreachable, you try the next one and so on...
That is something your SMTP server can handle for you too.
If you really want to build that logic yourself, please have a look at the DirectSend method of the SmtpClient class of this open source project I'm involved in.
As #TomTom points out, the entire mail infrastructure depends on SMTP. What you can do is to skip the output (relaying) SMTP server and send the message directly to the receiving SMTP server.
To do that you need to create some kind of queuing mechanism (there is no guarantee that the receiving SMTP server can serve you when you try to connect) and that you can look it up.
MX records are entries stored in DNS servers and are used to find SMTP servers. You can find a article here with a MX lookup example: http://www.codeproject.com/KB/IP/dnslookupdotnet.aspx
However, I DO recommend that you install a local SMTP server and let it take care of the above mentioned issues.
Yes, Basically figure out where to sent the email and send it. i.e. a DNS MX lookup for the domain to find out the SMTP server.
Every email needs an SMTP server on the receiving side.
You can use gmail or yahoo SMTP server, if you don't want to install your own.
Before sending mail you first need to authenticate, otherwise sending mail is not going to possible.
You need access to some kind of email server to send your email, and your email will most likely pass through one or more SMTP servers on it's way to the recipient. However, the email server you connect to might let you send the email without using SMTP. For example, Exchange might let you use MAPI or CDO to send emails. Though I think that CDO is not officially supported by .Net and simple MAPI is deprecated in Windows and should not be used. You might be able to use Exchange Web Services as described here: Introducing the Exchange Web Services Managed API 1.0
If you have another email server than Microsoft Exchange, that server might have some kind of API you can use.
Something I do often is to create gmail account and send through that account.
You just need your SmtpClient to connect to the host smtp.gmail.com on port 587 with the username, password, and enableSSL property set to true.
Related
What happens when the outgoing mail server is not part of the local domain? For example, I work for company xyz.com and our smtp server is mail.xyz.com. We host client sites in a multitennant application. We allow our users to point to their own smtp server using email configurations we store in our database.
The code we use to send emails loads the configuration with the smtp information and the authorization needed to send an email on behalf of our clients through their email system.
Currently we are running into concurrency issue that is causing timeouts for various clients when notifications are being processed. They are currently configured to be sent immediately. I've read that moving to the local pickup directory can solve this issue.
I am concerned if I specify a path like C:\Temp\Mail but use an SMTP connection to a clients mail server is that going to work? Doesn't the email being created and sent from the pickup location need to be on the same domain as the smtp server?
How will the clients SMTP server know .eml file has been generated for their domain and needs to be sent out without having to change our client's environment? If someone can provide any information as to how the SMTP and Specified Pickup Locations work I would greatly appreciate it.
The basic operation of an SMTP server in this sense is to monitor a specific set of folders and perform an action when an event occurs. Where your concern is is in that a file dropped into the pickup location is parsed and sent.
The basic SMTP operation allows any email server to send any email regardless of the domain that the email says it is from. This obviously caused issues with fraudulent emails and has been mitigated originally by Designated Sender and further extended via SPF, DIM, and DMARC.
So what your client would need to do is to have their SMTP setup properly and configured for your email domain(s). On your end it would be recommended to only allow the Designated Senders generate emails, and set up SPF etc for those clients as well
Microsoft has a good article on the SMTP basics How SMTP Works
Google has plenty of lists for SPF, DKIM, and DMARC as well.
I know there many articles on web regarding sending emails from code/C# and I have read many of them before posting here, but I still don't see a clear picture of how to implement my requirements:
Scenario:
My application on mydomain.com receives a request to send some kind of email (from: someone#mydomain.com, to: someone#gmail.com/anyother.com).
I need to make some manipulations on email content.
After I modified a message, I need to send it directly to recipient.
Under directly to recipient I mean that I want to send it to recipient by our servers and not using some kind of SMTP service/relay.
So as I understand I can install some SMTP software on our servers and send using System.Net.Mail.SmtpClient to our server and it will deliver it to recipients using SMTP Relay or some other way that coded inside that software...but, I would like to make it without using SMTP Server software...
Till now I found that I need to discover MX record for recipients domain, so let's say I found MX record for gmail.com (gmail-smtp-in.l.google.com), but how do I send email to that MX Record from my own C# code?
Does System.Net.Mail.SmtpClient suitable for this task?
Where I can find examples of how to do it?
From my previous expirience with SmtpClient, I need to provide SMTP server address (optionaly port), credentials, but in my case, of course I do not have credentials and I'm not sure how to get the correct port (does all servers from MX records has port 25?).
Thanks!
I was working on an application which would send emails automatically at specific time intervals to a valid email. Searching through the internet I found that most of the codes use the existing email accounts such as gmail.com to send email by logging in as an SMTP client. But my problem is that I won't be knowing the smtp server name of the users email(since the user is not generally aware of these things though he will be knowing the login/passoword). For example,
someone#gmail.com should give smtp.gmail.com and port number (465)
someone#nextek.net should give mail.nextek.net and port number (?)
someone#screaming.Net smtp.tiscali.co.uk and port number (?)
I got the MX records using the domain name of the email address, but I realized that it actually gives the available incoming SMTP server names.
For example gmail.com would give gmail-smtp-in.l.google.com along with four other server name if I ping using nslookup in command prompt.
Also what is the advantage of sending email by using an existing SMTP supporting email than sending directly by looking up the email server name through dns? Or is it not possible?
Correct me if I am wrong, since I am not much familiar with the protocols.
If you're not familiar with the protocols, it doesn't make sense for you to try to implement the protocol.
Generally, an application like yours doesn't need to worry about the details of the SMTP protocol. You would use an existing SMTP client library for your platform (I'm sure there is one for .NET you can use), and connect to an MTA (your MTA, not the recipient's), give it the email to send, and you're done. The MTA will take care of all the SMTP protocol details of figuring out how to get the email to the recipient.
Sending email is very similar to dropping a letter in the post box on the corner, and letting the post office figure out how to deliver it. You don't need to know which vehicle to put it on, or where the recipient's local post office distribution centre is, or any of those details.
You may choose to set up your own MTA using something like Postfix, or you can send email through your own Gmail account (of course you'll need a Gmail account and password before Gmail will let you do that).
I have an MVC3 web application written in C#. I am using McvMailer to send emails from within the application, which is all working fine.
The issue i have is that our smtp server is not anywhere near the web server that will be hosting the application, and that it is possible that on occasion the smtp server may not be available.
I need to be able to detect whether or not the smtp server is available before giving a user the option to send emails. Thus far the best i have come up with is to ping the smtp server using the solution from #John Leidegren answer in this post.
However, it appears that the router is responding to the ping and not the smtp server. Baring in mind that the main cause for the server not being available would be the internet connection failing, i could probably live with this solution if i had to, but it would be nice if i could ensure the availability of the smtp service prior to attempting to send emails.
Any ideas?
Yes, ping is a good start, but to determine if the SMTP gateway is available, issue the HELO command through the SMTP port.
I'll try to find a good example.
Edit:
You're in luck. Here's a complete TELNET client written in C#. https://www.nuget.org/packages/Telnet
I am able to send emails using the typical C# SMTP code across Exchange 2007 as long as both the from and to addresses are within my domain.
As soon as I try to send emails outside the domain I get:
Exception Details: System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: 5.7.1 Unable to relay
How can I get exchange to accept my email and send it out to the internet?
Try #2... How about using a Exchange Pickup Folder instead? They are a faster way to send emails through Exchange because it just creates the email and drops it in the folder, no waiting to connect to the server or waiting for a reply. Plus I think it skips the whole relay issue.
Configure youur SmtpClient like so:
SmtpClient srv = new SmtpClient("exchsrv2007", 25) {
DeliveryMethod = SmtpDeliveryMethod.SpecifiedPickupDirectory,
PickupDirectoryLocation = "\\exchsrv2007\PickupFolder"
}
...
Authenticate to the exchange server.
http://msdn.microsoft.com/en-us/library/system.net.mail.smtpclient.credentials.aspx
DefaultNetworkCredentials returns
empty strings for username etc and
causes this exception...
Here is an example, and here is another of sending authenticated message with System.Net.Mail.
You'll need to get your exchange admin to configure exchange to allow sending outside the domain. In my experience they've been reluctant to do so because of spam concerns.
If its' for limited use, you can set up server-side rules in exchange to forward messages meeting certain criteria outside the domain. You might be able to use VBA in these as well to pretty things up, but I am not sure.
Have you set up the exchange server to allow relays from your web server? I had the same problem when switching to Exchange 2007.