setup POP3server for the internet - delphi

I have built several applications in delphi using the indy components suite(version 10.5.2 i think) and they all are working. I have just finished setting up the POP3server and it works locally. I can see mail sent locally on there. I have been using "localhost" as my hostname. However, i want to graduate to a higher level of function. I want to be able to receive email from the internet such from msn, gmail, yahoo ... The problem is I don't know how to do this. What address should I be using inorder to do this? So far "myhouse#localhost" has been working but only internally; can't seem to get external mail in there. Is it possible to receive mail like this? Thanks.

You need to register a domain, and then setup its DNS records (in particular, its MX records) to point to your server machine. That way, when an email is destined for any "#yourdomain" address by any sending service, it will be routed to your server machine (which needs to run an SMTP server to receive emails - POP3 is for downloading emails from your mailbox, not for putting emails into it). If your server does not have a static IP, then you need to use a service like DynDNS to mange the DNS records for you so they can account for your dynamic IP whenever it changes.

"The Internet" doesn't use POP3 to send and receive email, it uses SMTP. Here's how email "flows" from the sending computer to the receiving computer:
Server needs to send email to address: myhome#localhost. The first thing it does is isolate the server name, that's the part after "#". Next it uses DNS to lookup the SERVER IP for the computer that's supposed to receive email for the given domain. DNS contains a special record for this purpose, it's called the "MX" record. You can use command line tools like dig on Linux or nslookup on Windows to find this address, or you can use an online tool like the one found at http://www.mxtoolbox.com/ (google found this site, I assume there are many others!).
If you try to locate the MX record for your "localhost" domain you'll obviously discover it's not possible, because it's not a fully-qualified name. You first need to get yourself an domain name, so you can register a MX record!
Things you need in order to RECEIVE email
Need an "real" IP address. Servers outside your local network need to contact your server, and they obviously need a way to do it. Make sure no routers along the way block SMTP ports.
You need to register an domain name, add a MX record and point it to your "real" IP address.
Need to run SMTP server software on your box. You can use Indy components to write one.
Things you need in order to SEND email
Theoretically sending email with SMTP is the easy part. You just contact the responsible server using SMTP and send email, that's the way the protocol works: any computer in the world may send email to any SMTP server.
Practically sending email is the most difficult thing you'd have to do, mostly because foreign SMTP servers don't trust you (ever heard of SPAM?). Here are some of the things you might need to do so foreign SMTP servers accept email from you. There's no definitive list because the protocol itself doesn't include a clear authentication mechanism, so every big SMTP server out there uses it's own heuristics to decide rather to accept email from you or not. You'll find yahoo especially fun!
You need to have REVERSE DNS for the IP you're using to send email.
You need to send from one of the SMTP servers listed in DNS as your MX servers.
Your DNS records need to have long TTL (this rules out Dynamic DNS services)
Many other things...
What people usually do?
eMail is hard, there's a surprisingly small number of full SMTP servers available for your own server: Exchange, Notes, Postfix, QMail, Sendmail. They're all notoriously difficult to configure. Most people would use hosted mail services, some people would use the SMTP services provided by the ISP, and very few would install one of the mentioned services.
If you really want to write your own SMTP server go ahead, but you might want to install one of the ready-made ones before, to get a bit of eMail and DNS experience. The Linux ones are cheap to install and may also help with development (you don't want to send too much bad email to your free yahoo address, you might get blacklisted!)

POP3 is a protocol to read email from a mailbox. The TidPOP3Server component implements a POP3 server (and AFAIK it has no host property to set...), while TidPOP3 implements a POP3 client. To read mail from GMail or any POP3 server you need a TidPOP3 component. The hostname to set is the DNS name the service instructs you to use (i.e. pop3.mydomain.com).

Related

Basic Confusion about ActionMailer RoR

I'm fairly new to Ruby on Rails and actually entirely new to website mailing. In a lot of example tutorials I see a "from" object assigned to, for example, "new#example.com". When I setup the emailing functionality on a localhost the RoR command prompt says that everything finished fine even when I keep "new#example.com" as the from object. Can I actually mail from a localhost port? What would I have to put as my "from" address in order to actually send mail from the my local web application? Just a regular email I have? How would it be authenticated to ensure that the "from" address is actually the real address?
It seems a really fundamental concept and I understand all the model/view/controller actions that have to be done to make it work but I'm confused I guess as to how it actually works
In general the from field can be anything.
Some mail servers may take action if they think that you are claiming to be someone you are not, such as blocking mail or marking it as spam (via mechanisms such as DKIM or SPF). These are done at the domain level, ie the mail server tries to work out whether the server talking to it is allowed to send email claiming to be from #example.com.
Other mail servers mail just silently rewrite your from field if they know who you are, for example if you are talking to the gmail smtp servers and have authenticated as bob then the from field will be set to bob#gmail.com, unless it is already set to an email address gmail knows you own.
By default, in development rails doesn't try and send email at all. For it to send email you need to configure the deluvery_method, usually this involves either setting it to :sendmail (if you have an appropriately configured instance of sendmail running locally) or setting to :smtp and also providing details of an smtp server to use.

reaching Gmail SMTP daily limit

In one of my Rails applications I'm sending emails through the Gmail SMTP server and everything just works, mails are not going to spam and so on ... But there's one thing that concerns me, the 500messages/day limit the SMTP has, currently I'm over 350/day. I didn't find any official Google page where they talk about the subject, just blog posts that seems to be reliable. Then my question is what do you suggest me in order to be able to send more than 500messages/day? I would love to keep using the Gmail SMTP.
Any help would be appreciated.
Don't use GMail for what it wasn't built for. It wasn't designed as a mass-email system, although Google definitely has the firepower to do this.
Instead, perhaps use something like SendGrid to send your emails. SendGrid is designed for this and is just as easy (actually, probably easier) to set up with than GMail.
You can consider using more than one gmail account to access the smtp server, however you may have problems with ip limits (couldn't find anything on their docs about it). Another option is performing dns mx lookups yourself and reproducing your own smtp server by directly delivering the messages to the user's emails - but that can increase the odds of you being tagged as a spammer as your ip is not whitelisted as sender.
I think the best way is to create another gmail account and trying to reroute your connection to use it when one of the accounts reaches the daily limit. A vpn connection can solve that for you.

Sendmail vs SMTP

A rails application in production should use smtp or sendmail to send mails?
SMTP is the protocol that is used by nearly all Internet hosts to send mail. This protocol is spoken by sendmail. Sendmail determines where to send your message and how.
Some mail programs (most, today) will connect directly to a mail server and speak SMTP to it. However, the "traditional" method - and arguable the better method - is to let sendmail do it.
There are two reasons for this: 1) nearly every program in UNIX that does what sendmail does is designed to be a drop-in replacement (this includes Postfix and Exim for instance); and 2) sendmail or its replacement was designed to handle mail and nothing else - by using sendmail you don't have to design a SMTP client.
The Mutt email client for UNIX is one email client that still refuses to talk SMTP directly to a mail server; a good (technical) description is on the wiki.
If you have a choice (on UNIX anyway) of talking SMTP directly or using sendmail, use sendmail - especially on servers.
As NDP already mentioned, they both work fine - that is, if your volume of messages doesn't exceed a certain amount.
For example, if your application can talk SMTP to either the local SMTP server (on IP 127.0.0.1, Port 25) or a server in the same subnet (i.e., over a low-latency link), and that server does not use any content filters before it queues a message, you will usually be able to submit a lot more mails over SMTP in a shorter time.
A useful link for Postfix may be General Mail Delivery Performance Tips - note the quote saying
Submit mail via SMTP instead of /usr/sbin/sendmail.
However, on modern hardware, if you don't plan to submit more than about 10 messages per second, you shouldn't notice any real difference.
Your question is incorrect - SMTP stands for Simple Mail Transfer Protocol whereas sendmail is the software piece to send the mail using this protocol.
Use sendmail.
They both will work fine. Action Mailer supports both.
I have used SMTP on several projects successfully. My sense was that this was a little more "standard", but I may be wrong.
I haven't used sendmail. My concern would be that it may be harder to set up in a development environment if you aren't developing directly on Unix/Linux. Where you can talk directly to any SMTP server -- even a remote one, -- you would have to install sendmail on the rails machine to get it to work.
The main problem I run into with email is sending messages asynchronously. Without a local SMTP server, a local sendmail instance is going to be more performant.
Either way, it looks pretty easy to switch if you decide you picked wrong.

Send emails (using Postfix) from two different domains

I have two Ruby on Rails applications, and two virtual domains (mydomain1.com and mydomain2.com)(using Apache+REE+mod_rails).
I use Postfix as mail server.
So I have myhostname = mail.mydomain1.com in main.cf
And that's because why the sender is always mail.mydomain1.com, no matter from which application I send emails.
I need all emails sent from application on virtual domain mydomain1.com have Received: from mydomain1.com, and from second Rails app on mydomain2.com — Received: from mydomain2.com
Is that possible?
Thanks!
Received: headers are added by the receiving server, which is simply doing a reverse DNS lookup on the connecting (sender) IP address. You won't be able to get the result you desire unless you can force Postfix to make its outgoing connections on a specific IP, and then bind an IP per domain to your server.
I guess there is a way to configure Postifx for using virtual accounts for seperate domains. Using this, you should be able to have both of your apps using different settings.
Maybe this helps:
http://howtoforge.org/virtual-users-and-domains-postfix-courier-mysql-centos5.1
or this
http://www.akadia.com/services/postfix_separate_mailboxes.html
Matt
That's a good question, but I don't believe there is an easy answer.
At one point in the past, the author of postfix stated "postfix makes delivery decisions on the basis of the recipient
address only. There is no logic for sender-dependent routing." That was years ago but it may still be true.
Some people have tried using two separate instances of Postfix. There's an article here that might help, although I have not examined it that closely.

want email from my server (postfix) to an email address on my domain to be delivered to google apps

I have google apps for receiving email. I get inquiries from people on info#[my-domain.com], which email is hosted on google.
Sometimes, I want my rails set-up to send emails from my own server, and that works fine. But when I want to send to an email address on my own domain, such as info#my-domain.com, postfix sees the my-domain.com and tries to deliver locally.
I understand that's normal, but I'd like to have those emails go to google apps rather than try to be delivered locally.
I know there's a postfix config file for aliases, but here, the email addresses are the same, just need to tell postfix not to try to deliver locally.
Any way to do this?
It sounds like you have two mail servers set up to act as the primary destination for email to your domain: Google Apps and your postfix server. You can't do that because, as you've found, mail sometimes gets delivered to one server and sometimes the other.
Presumably you want Google Apps to be the primary destination. That is, mail for your domain should go to the Google servers, not yours. You will need to re-configure postfix so that it is not the mail server for your domain.
Edit the /etc/postfix/main.cf file and look for the mydestination line. Remove your domain from that line.
I don't normally use postfix, but I think if the line looks like this, you'll be good:
mydestination = $myhostname localhost.$mydomain localhost
Let's say your server name is "test1" and your domain is "example.com." The following addresses would be delivered locally:
info#test1
info#localhost.example.com
info#localhost
But mail to info#example.com would go to Google Apps because postfix is not configured to accept mail for simply "example.com."
I get around it by doing this http://souptonuts.sourceforge.net/postfix_tutorial.html. Basically have that mail sent through one of your google domain accounts instead of locally.
Either, as Barry Brown suggested, tell postfix that my-domain.com is not local by removing it from $mydestination on the postfix box, or if that's not practical, use virtual aliases in Postfix to rewrite that specific address (info#my-domain.com) to the google-hosted address you want to deliver it to.
Virtual aliases in Postfix are not just for the virtual alias address class; they are a general-purpose pre-queue address rewriting mechanism. Sendmail-style aliases (depending on your distribution, either /etc/aliases or /etc/postfix/aliases) are used by the local delivery agent and only apply to the local address class. You could, of course, use sendmail-style aliases to forward mail for "info" to some-address#your-google-hosted-domain.
The documentation at postfix.org is pretty good. Try
http://www.postfix.org/STANDARD_CONFIGURATION_README.html
http://www.postfix.org/ADDRESS_CLASS_README.html
http://www.postfix.org/ADDRESS_REWRITING_README.html
http://www.postfix.org/VIRTUAL_README.html

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