We send loads of e-mails to clients/the public, but our current set up is antiquated and old, and to be honest, I really don't know how it works at all...
What's a good way to re-do it? We get loads of complaints from people not receiving e-mails and also loads go into their junk folders...
Our software is asp.net, and I am rewriting the whole legacy system which creates and sends e-mail actually in the code. I would have thought the correct way would be to send the e-mail to some kind of server to send out rather than doing it this way, but sending e-mails out is new to me.
Can anyone point me in the right direction to learn about this stuff? Our team spends a huge amount of time dealing with people who don't get e-mails and if we had a reliable system that we could easily debug, it would make life easier and save money.
All I know about e-mail is that an Exchange server is perhaps involved but we don't actually have an exchange server (yet, should we get one?)... All advice/links to articles to read welcome;)
At some point, your code will be calling (depending on which version of the framework you're using) something like (.Net 2.0+, using System.Net.Mail):
SmtpClient smtp = new SmtpClient(mailServer);
smtp.Send(emailMessage);
or (.Net 1.1 using System.Web.Mail):
SmtpMail.SmtpServer = mailServer;
SmtpMail.Send(emailMessage);
In either case the string mailServer will be the name/address of the server you are sending the emails out from - this probably isn't an exchange server, it's more likely to be an SMTP server, sitting on your IIS server or host.
On the server side:
Make sure that this server is set up to send the quantity of emails you're sending out - I can't really help too much here - try ServerFault.com I guess ;)
See if you can turn on logging, or at least monitor the BadMail queue - that will give you some indication of whether the problem's at your end or somewhere out there.
There are a number of things that will cause a users mail server or client to consider your emails as Junk, and not accept them, however the most common ones are:
The email comes from a different domain to the "from" address - ideally, you should ensure that your emails are sent from an address with the same domain as your server. If this is not the case, then you'll need to add a Sender Policy Framework header to the server with the address's domain to tell other mail servers that your SMTP server is allowed to send email on your behalf.
The email contains a high number of links in comparison to the non-link text.
The email "looks" like spam - i.e. it matches various model spam emails.
The user hasn't entered their address correctly (you'd be surprised).
Following on from that, make sure that the From address actually exists at your end - that way you can monitor bounce-backs from remote servers and see what reasons they are giving for rejecting your emails.
Depending on the type of emails, and the amount of money you have to spend, you might want to look at using a 3rd Party mailing solution - again sadly, this is outside my area of expertise.
Before you start, it's worth spending some time making sure you understand SMTP.
The MSDN documentation for System.Net.Mail.SmtpClient has some basic working examples of how to send email in .Net.
The hints page at MailChimp and CampaignMonitor have some decent general advice about composing and sending bulk email, whether for marketing purposes or not.
Related
This is a theoretical question.
imagine an aspnet website. by clicking a button site sends mail.now:
I can send mail async with code
I can send mail using QueueBackgroundWorkItem
I can call a ONEWAY webservice located in same website
I can call a ONEWAY webservice located in ANOTHER website (or another subdomain)
none of above solutions wait for mail operation to be completed.so they are fine.
my question is why I should use service solution instead of other solutions. is there an advantage ?
4th solution adds additional tcpip traffic to use service its not efficient right ?
if so, using service under same web site (3rd solution) also generates additional traffic. is that correct ?
I need to understand why people using services under same website ? Is there any reason besides make something available to ajax calls ?
any information would be great. I really need to get opinions.
best
The most appropriate architecture will depend on several factors:
the volume of emails that needs to be sent
the need to reuse the email sending capability beyond the use case described
the simplicity of implementation, deployment, and maintenance of the code
Separating out the sending of emails in a service either in the same or another web application will make it available to other applications and from client side code. It also adds some complexity to the code calling the service as it will need to deal with the case when the service is not available and handle errors that may occur when placing the call.
Using a separate web application for the service is useful if the volume of emails sent is really large as it allows to offload the work to one or servers if needed. Given the use case given (user clicks on a button), this seems rather unlikely, unless the web site will have really large traffic. Creating a separate web application adds significant development, deployment and maintenance work, initially and over time.
Unless the volume of emails to be sent is really large (millions per day) or there is a need to reuse the email capability in other systems, creating the email sending function within the same web application (first two options listed in the question) is almost certainly the best way to go. It will result in the least amount of initial work, is easy to deploy, and (perhaps most importantly) will be the easiest to maintain.
An important concern to pay significant attention to when implementing an email sending function is the issue of robustness. Robustness can be achieved with any of the possible architectures and is somewhat of an different concern as the one emphasized by the question. However, it is important to consider the proper course of action needed if (1) the receiving SMTP refuses the take the message (e.g., mailbox full; non-existent account; rejection as spam) and (2) an NDR is generated after the message is sent (e.g., rejection as spam). Depending on the kind of email sent, it may be OK to ignore these errors or some corrective action may be needed (e.g., retry sending, alert the user at the origination of the emails, ...)
It is quite easy to update the interface by sending jQuery ajax request and updating with new content. But I need something more specific.
I want to send the response to client without their having requested it and update the content when they have found something new on the server. No need to send an ajax request every time. When the server has new data it sends a response to every client.
Is there any way to do this using HTTP or some specific functionality inside the browser?
Websockets, Comet, HTTP long polling.
It has name server push (you can also find it under name Comet technology). Do search using these keywords and you will find bunch examples, tools and so on. No special protocol is required for that.
Aaah! You are trying to break the principles of the web :) You see if the web was pure MVC (model-view-controller) the 'server' could actually send messages to the client(s) and ask them to update. The issue is that the server could be load balanced and the same request could be sent to different servers. Now if you were to send a message back to the client you'll have to know who all are connected to the server. Let's say the site is quite popular and you have about 100,000 people connecting to it every day. You'll actually have to store the IPs of each of them to know where on the internet they are located and to be able to "push" them a message.
Caveats:
What if they are no longer browsing your website? You see currently there is no way to log out automatically if you close your browser. The server needs to check after a fixed timeout if you have logged out (or you send a new nonce with every response to prevent the server from doing that check)
What about a system restart/crash etc? You'd lose all the IPs that you were keeping track of and you are back to square one - you have people connected to you but until you receive new requests you can't really "send" them data when they may be expecting it as per your model.
Let's take an example of facebook's news feeds or "Most recent" link close to the top right - sometimes while you are browsing your wall you see the number next to most recent has gone up or a new 'feed' has come to the top of your wall post! It's the client sending periodic requests to the server to find out what was updated rather than the other way round
You see, it keeps it simple and restful. You may feel it's inefficient for the client to "poll" the server to pull the data and you'd prefer push, but the design of the server gets simplified :)
I suggest ajax-pulling is the best way to go - you are distributing computation to the client and keeping it simple (KIS principle :)
Of course you can get around it, the question is, is it worth it?
Hope this helps :)
RFC 6202 might be a good read.
My asp.net (mvc2) web app webinar registration system sends emails with connection info. Currently we just loop thru the list of attendees and hit a System.Net.Mail.SendMail for each. We send mail via our GoogleApps account (non-premium).
My use case is to send < 50 emails at a time and the system's been working fine. On the occasions where the number pushes a 100 addresses I find error returns with the message:
Service not available, closing transmission channel. The server response was: 4.7.0 Try again later, closing connection. (MAIL) g31sm4823143ibh.4
Is this message specific to Google's servers (searched on the phrase - seems like 'no'). Is there a recognized 'best practice' for sending emails by code?
Could it be that gmail just notices that you're sending a lot of messages in a rapid rate indicating it to them you're a spammer (in their eyes)?
If you have hosting I suggest you talk with your provider and see what they can offer you or provide an email address with which you can send more messages, in a controlled way of course.
GMail definately has a sending limit.
I dont think its widely publicised, but it certainly sounds like you're hitting it.
Slightly old question for a followup, but to help others landing here, things have changed since then (and they constantly change):
A registered G Suite user can't relay more than 10,000 messages in a 24-hour period, and can't relay messages to more than 10,000 unique recipients per 24-hour period. Users exceeding either of these limits see the error "550 5.4.5 Daily SMTP relay limit exceeded for user."
https://support.google.com/a/answer/2956491#sendinglimitsforrelay
i have to write application for sending newsletter.
what is the best way to send newsletter thoundands of users?
My requirement is
Each mail is seprately as To :
Every mail has unique Unsubscribe link
Is is good to use SMTP mail class of .net?
I look aound may questions in so but can't decide which approcah i should go?
There are many suggestions
Multi threaded Windows service
Use Mail Server
Add thread.sleep(2000) between each send.
can anyone suggest good way to imepement this?
I would not recommend asp.net webpage to send, even if you do start it in a separate background thread. I would think you run the risk of the server recycling your process in the middle of the send, which would mess it up. You really need to write some kind of separate service or application to send your emails.
The simplest option would be to just create a quick and dirty console or windows form application.
Also logging is critical just like the other poster said. If it fails you want to know exactly what got sent out and where it stopped so that when you restart it you don't mail all the people who it did work for again. You want to be able to input the starting point for the send, so if you need to restart at number email #5000 you can.
The classes in System.Net.Mail namespace will work just fine for sending your mail.
One of the biggest problems will be finding a email host that will let you send so many emails. Most email hosts have throttling and sometime it changes depending upon server conditions so if the server is being heavily used then the email limits will be more restrictive, and you may only get to set 500 emails per hour.
We have a newsletter that goes out to around 20000 people as separate emails and we had to play around with the delay between emails until we found one that would work for our email host. We ended up with 1.2 sec between emails, so that might be a good starting point.
I think there are email hosts specialize in bulk mailings though so if you get one of those it might not be a problem.
Also if you host your own email this may not be a problem. And if you do host your own mail you will have the option of dropping the mail in the pickup directory and you could just dump it all in there as fast as you want, and let the email service pick it up at it's own pace.
EDIT: Here is the settings to add to the config file for setting the pickup directory
<system.net>
<mailSettings>
<smtp from="support#test.com" deliveryMethod="SpecifiedPickupDirectory" >
<specifiedPickupDirectory pickupDirectoryLocation="Z:\Path\To\Pickup"/>
</smtp>
</mailSettings>
</system.net>
Definitely do not do this in ASP.NET. This is one of the biggest mistakes that new web developers make.
This needs to be a windows app or service that can handle this much volume.
I've written pages that send emails, but not nearly the volume yours will. Nonetheless, I would recommend the following based on code I have implemented in the past:
Use the web application to write out the email and all the recipient addresses to database table(s).
Have a process that is outside of ASP.NET actually send the emails. This could be a vbs file that is set up as a scheduled task, or (preferably) a windows service. The process would take the text of the email, append the unsubscribe link, and once sent successfully flag the database record as sent. That way, if the send fails, it can try again later (the send process loops over all the records flagged as unsent).
If you need a log of what was sent and when, you just need to keep the sent records in the database tables. Otherwise, just delete the records once sent successfully.
IMHO sending emails within the ASP.NET worker process is a bad idea because you don't know how long it will take and if the send fails there's little opportunity to retry before the page times out.
Create a webpage to "Design" the newsletter in. When they hit Send, queue the newsletter up somewhere (database) and use another program (windows service, etc) to send the queued letter. This will be many times more effecient and potentially fault tolerant if designed properly.
I have written a Newsletter module (as part of a bigger system) in ASPNET MVC 2, Entity Framework and using the System.Net.Mail namespace. It is kicked off in view and actually just runs in a controller with a supporting method to do the send. As each email is sent I track whether there is a hard bouce (an exception is thrown) and I update that database record stating a fail with the exception, otherwise I update the record stating success. We also do personalisation so we have 'tags' that get replaced by an extra field in the database (stored as XML for flexibility). This helps handle an unsubscribe function.
My code is quite simple (please don't flame me for using exception handling as business logic ;) and it works like a charm.
This is all done on a VPS at http://maximumasp.com which also hosts 4 sites with pretty decent traffic. We use their SMTP servers. We notified them that we needed this service and have had no problems relationship-wise.
We had 2GB of RAM on the machine running Windows 2008 and it was doing 6 emails/sec. We bumped it up to 3GB as the web sites needed it and now the mailout is doing about 20emails/sec. Our mailouts range from 2,000 to 100,000 email addresses.
In short, ASP.NET can be used to handle a mailout, and if you add in some logic to handle record updating the worry of losing your way mid-send is mitigated. Yes there are probably slicker ways to do this. We are looking in to MQMS and threading, and separating that out to windows service to make it more stable and scalable as we put more clients and larger lists on, but for now it works just fine with reasonable reporting and error handling.
Hai Guys,
My application deals scheduled mail concept (i.e) every morning 6.00 am my users gets a remainder mail about their activities for the day... I dont know how to do this.... Many told use windows service but i will host my website on a shared server i may not get rights to do windows service... Is there any dll for sending mails at a schduled time through asp.net application ..please help me out guys......
You cant do much in a shared hosting. Try upgrading your hosting or else write a windows service, to run on your machine, which will call an asp.net which can send out emails. Of course your machine has to be switched on all the time or at least during 6:00 AM :). You will have to take proper steps to avoid unauthorized request for that aspx page.
you can check this article too: http://www.codeproject.com/KB/aspnet/ASPNETService.aspx
You can't really do this with ASP.Net. ASP.Net is for web pages - which are reactive to HTTP requests.
You need a scheduled task or a service. All a website can do is respond to requests. I guess you could program the functionality into a web page and have a remote process request the page every morning - but what happens if someone else requests the page?
You can either have a program that runs constantly and has a timer or a loop that checks the time of day and then sleeps for a really long time and when the timer goes off or it's the right time of day it sends an email, or you can launch a program as a scheduled task. The first method can also be implemented as a service if you would like. Keep in mind you dont need ASP.Net to send emails, all you need is a console application that uses System.Net.Mail. Check out the mailer sample on MSDN for a very simple idea.
One other thing you can consider: IIS has an smtp service that you can install and it uses a pickup directory to send mail. You write an email to the pickup directory as an .eml file and IIS grabs it and sends it almost immediately. If you do that, you'll still have to write the emails (System.net.Mail will write the .eml files from a MailMessage, just set SmtpClient.DeliveryMethod to SpecifiedPickupDirectory or PickupDirectoryFromIIS and call SmtpClient.Send) but it will then send them for you. You'll still need to schedule something somehow so this might not be all that more useful but I thought I'd at least let you know that it exists.
One thing to be aware of: when the IIS SMTP service reads the send envelope of the .eml file, the order of the Sender and From headers is significant; if the From header appears before the Sender header then the MAIL FROM command will use the From header, which is incorrect (and MS won't be fixing this one). This appears to be an issue ONLY with the IIS SMTP service as it hasn't been reported anywhere else that I'm aware of. Reversing the order of the headers is the work-around. By default SmtpClient always writes the From header first. I'm aware of the issue and IIS isn't fixing it but I may be able to get a fix into SmtpClient for the .NET 4.0 RC build that re-orders the headers for you but no promises.
If you happen to have it handy (and I assume you do), you can use a SQL Server Agent job to make a request to an ASP.NET page that sends the email.
Here's some example code:
http://nicholasclarke.co.uk/blog/2008/01/16/web-request-from-sql-server-via-c/
Of course, since you're using SQL Server to call CLR code anyway, you could just have that code send out the emails (via System.Net.Mail) rather than requesting a page on IIS to do so. To do this, SQL Server would need:
Access to all of the data needed to send the emails
Outbound firewall access to send an email
CLR code that encapsulates all of the logic needed to know where/what to send.
Okay this is interesting, and what I did fits silky's definite of 'cheating', but no it was pretty cool for me.
What I did was spawn a new thread from ASP.Net code (it was possible on that host), and that thread did the scheduled job.
I checked whether the thread was alive (which is pretty easy) on every visit to the website (not so reliable I know, but it worked cause that website has plenty of visitor).
If at all you do this
Treat this as a stop-gap while you arrange to get a dedicated host or VPS.
Rest assured that the hosting company will kill your thread and withdraw permissions when they discover you're doing this.