I need a SMTP server for Windows Server 2012 so that I will be able to intercept incoming emails from my C# application and display it to my clients via an ASP.NET application. Sorry if this would look like a trivial question but i cant figure out where should i start from.
The most obvious Windows SMTP server is Exchange, although there are plenty of free ones (XMailServer, MailEnable or the lighter-weight Papercut, which might serve your purpose) - I've not used anything other than Exchange, but a Google search will find you a tonne of them.
Is this just for sending messages from client to server, though? Unless there's some reason you need to have these messages as emails, it seems unlikely the overhead of setting up an entire email system, sending an email and then extracting the message and putting it into a web page is the best solution to your problem - have you considered a lighter-weight client-server messaging system, such as DotNetMQ or simply sending your own messages directly through TCP sockets?
Related
First of all, my apologies for the most likely inappropriate wording of the question. Not knowing exactly how to describe the problem I need to solve has been a major roadblock in my attempts to solve it.
I currently have a web server (Laravel) that needs to communicate with a SQL server in a different network, which only permits outgoing traffic. I made it work by having a C# daemon, running inside the SQL server's network, poll it for data and send it to the server through HTTP POST requests.
However, I now need the web server to communicate with the daemon. Something as simple as:
someone looks up a username on the web server
the server requests the daemon to look it up on the database
the daemon returns whatever information it found to the web server.
What I'm struggling with is finding the best way to do this.
All I need is for the server to be able to push requests to the daemon in real time. The daemon can reply through HTTP POST requests to the server, just like it is doing already. The best potential solution I have found is WebSockets, but it also sound like it might be overkill.
Am I missing something or are WebSockets indeed the way to go?
Guzzle is what I use to make HTTP requests to external APIs in Laravel.
Websockets are mostly used when the user has no control over the responses, for example, a chat window. But if you need to, for example, click a button and wait for the response Guzzle is enough.
I have many applications across an enterprise environment and they all use different methods of sending emails. Some send directly through an exchange server, some queue up locally in an SMTP queue and others call a a web service that then sends the email.
I'm trying to decide on the best way to get guaranteed delivery of emails. If our Exchange server goes down, then the applications that send to it directly can no longer send emails, also any emails sent during the down time never get anywhere. I would also like to implement a universal templating solution that all applications can share.
Are there any pre-built solutions to this problem, or do you have an insight on how to handle this issue?
We solved this by creating a web service that sends all our emails. This web service uses the
System.Net.Mail.SmtpDeliveryMethod.PickupDirectoryFromIis
setting, which essentially saves the files to a spot on the disk, tries to send them via the main SMTP server, and if the server is unavailable, they sit in the directory until it BECOMES available.
Guaranteed delivery, as long as the web service is up. Since we have redundancy checks in place, this is almost never an issue. If it is, we treat it as an error in code and handle it.
edit - added
I forgot to mention that XSS is a concern even in an email, so be sure to use something like the Microsoft.Security.AntiXss library, which contains functions like GetSafeHtmlFragment to strip out potentially dangerous scripts before outputting html to an email.
http://msdn.microsoft.com/en-us/security/aa973814.aspx
http://msdn.microsoft.com/en-us/library/aa973813.aspx
I have heard good feedback about Postmark. Maybe a service like that could be solution as it has several integration points.
http://postmarkapp.com
We have used HMailServer (on windows platform) which is freeware. Configured the max retries to too many & used external smtp to relay the emails. our applications ques up emails on the HMailServer and that server relays it further. with the max retries configured to be many if at all the main smtp servers are down we can assure that the email are delivered - but though there is no gurantee if there is huge downtime with main smtp relay servers.
I do this by queuing email to a SQL server database. Any ACID compliant database will work or you can use MongoDB with 'safe mode' inserts but if you really need guaranteed then use SQL server or MySQL. This way if your mail gets into the database it is 'guaranteed' not to be lost and your app doesn't have to think about it. You could use a web service or just make a shared assembly with a static public method in a class to drop your email in the db for you.
Include a column for status like 'new', 'delivered', 'recipient mailbox temporarily full', which you can represent with numeric values and keep a TimeToSend column, which starts out as the time when the email is queued in the database.
Then you have a mail app, that you can have run once a minute as a windows scheduled task. Make it as a console app. When it loads, it checks if an instance of it already running and if there is one, it exits. When running:
1. Attempts to deliver each mail to mail server. Query the database for all mail where the TimeToSend is older than now.
2. If mail is delivered to mail server, mark it logical deleted.
3. If any mail can't be delivered, advance the TimeToSend column for them to 10 minutes from now.
4. Delete records from table that are logically deleted. You can do this in the app or you can do it by having a sql job do it.
As mentioned earlier, you can utilize a web service that you can usually POST JSON to using an HTTP request. Here are a bunch of choices:
PostageApp (Ours!)
SendGrid
PostmarkApp
Amazon SES
They all have different feature sets and offerings, so definitely give them all a spin and figure out which you prefer.
(Full Disclosure: I am the Product Manager of PostageApp.)
Im looking to send email vi a .net 3.5 form (C#)
Ive seen a few posts elsewhere and got the thing running ok for certain addresses but not for others, eg gmail accounts.
The finished app will have to pick up addresses from a database so Im having to cater for a lot of possibilites.
Im not looking to have my work done for me, just a shove in the right direction would be cool!
thanks
DD
Is it possible the gmail accounts are blocking you as a spammer? If you're sending out a lot of emails, or if there is a configuraiton issue on your server, they may have blacklisted you.
If the emails are going out from your server OK, but not reaching ALL of the recipients but is reaching SOME, then there is likely an issue outside of your direct control. An email goes through several servers in between your server and the enduser's inbox (and that's the case even if the inbox is on google's server for gmail.)
That said, there are things you can do to reduce your likelihood of being blocked/blacklisted.
This is a good place to start: http://www.andreas-kraus.net/blog/tips-for-avoiding-spam-filters-with-systemnetmail/
and then here is where to go from there. (Sorry - it's just a google search, but I gave you the relevant terms, at least.) http://www.google.com/search?q=system.net.mail+blacklist+spammer&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1
Finally, here's a very good resource with a cool URL. Perhaps the force will be with you if you learn these ways, young padawan.
http://www.emaildeliveryjedi.com/avoid-spam-filters.php
But getting back to your original question - everything you need to know about how to write code to send an email is covered here: http://www.systemnetmail.com/ It's the same for all versions of .NET from 2.0 on uo through the current 4.0.
And I'm sure you're already aware, but in case you're not, be sure you're familiar with the CAN-SPAM act. http://business.ftc.gov/documents/bus61-can-spam-act-compliance-guide-business
In addition to the great info from David Stratton...If you're certain that the gmail accounts are not receiving your emails, i.e. you've waited for sometime, checked the gmail spam boxes, and you've checked your SMTP server logs to ensure that Google is not sending any particular messages back to your SMTP server, then you may have run into a case of grey-listing / black-listing.
Black-listing can occur when a mail service has decided that the IP address of your mail server is a spamming server. It can happen under different scenarios, shared scenarios can be quite common.
One shared scenario: Let's say you recently acquired a new IP address, but it was recycled by your hosting provider from a prior client of theirs, who was a spammer. There is no guarantee that the IP address would be white-listed.
Another shared scenario: You're sending emails on a shared hosting website, where your SMTP service that you are using is shared with other clients of the SMTP service provider. It may be that one of those clients used the SMTP service maliciously or without following appropriate SPAM rules that gmail abides by.
Your best bet is to contact Google to commence a white-listing process. Providing you follow their requirements, they should eventually unblock emails originating from your service.
Can anyone recommend a simple and reliable method of sending email notifications and possibly log files attachments from a C# program without requiring the installer or the user to configure the program by specifying server details and email addresses etc.
(Mainly because they won't know the details, but also because they could change)
The program will normally be run as a service of a Windows Server, but can be run on a client.
I tried connecting to our own mail server and sending a email to myself, but some ISP's are blocking Port 25 on all servers but their own, so that method isn't working reliably.
Tried sending email through gmail but that was less successful as the port they used was blocked by firewalls. Ditto webservices connecting on weird ports.
Trying to use the local smptservice but did not work either.
It would be nice, but not essential if it was not dependant on my own Internet connection/Servers. (Don't mind them being delayed, but prefer them not to get lost).
Are there any webservices on http/https that allow you to do this sort of thing?
TIA
try using cdosys
http://support.microsoft.com/kb/310212
http://www.eggheadcafe.com/articles/20030316.asp
May have discovered the solution.
Was catching up on my blog reading over the weekend and came across a recent entry on Coding Horror and the very first comment mentions PostMarkApp which seems to do everything I need (and almost everything I want, apart from attachments which they are considering).
I'd like to make a stripped down email client for my pre-schooler using Silverlight 3 and pulling email from a Gmail account.
I'll have some filters setup in Gmail so that only a subset of email is given a particular label, similar to creating a whitelist. Then, I'd like to pull those emails with that label to the Silverlight client. I'd like to avoid running any of the messages through the server (so that I can share this application with friends and not have their email app require a server).
I've never written any sort of email client (POP3 or IMAP) and am not sure if this will even be possible. Looking through the various libraries available for retrieving via IMAP, I can't find references to using a browser-limited client such as Silverlight.
Also, I'm guessing I'll be able to send via .NET built in SMTP objects in Silverlight, but haven't tested this yet either.
Can anyone point me in the right direction; tell me why this may or may not be feasible; or relate their own experiences regarding this type of challenge?
Silverlight does not yet allow arbitrary socket connections, which you would need to connect to an IMAP server on the privileged port of 143. Silverlight can only connect to servers, even with a client access policy file, on ports 4502-4534.
Your only options are to proxy to gmail via a server on those ports, or just do the IMAP work on the server and serve it down to the client app over HTTP.
Sorry about this-- enhanced socket support is always being looked at, but it has scary security implications and hasn't been implemented yet. Good luck finding a solution to your scenario.
There is a great example of a Silverlight based mail client here:
http://silvermail.com.au
I use this regularly to check my personal email from work, and I know that it works with GMail.
Hope that helps.