Can't connect to local mail server (MDAEMON) from outside [closed] - email

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I have a mail server in our local network that run through Kerio firewall. I open tcp 110 port, and try to get mail from Mdaemon to Gmail, but all in vain.
Thanks in advance.

I'm sure that this question's been abandoned... But, I'm waiting for a server to reboot and there's nothing better to do atm.... MDaemon's a good product that we've used for quite some time (with some headbanging, unfortunately).
TCP Port 110 is used by the POP protocol, normally (but not always) used by mail clients to read email from a mail server.
There's nothing special about how MDaemon uses POP, other than that it can be turned of for the entire server or for individual accounts.
POP isn't what's used to get mail from your MDaemon server to Gmail, though (unless you're telling your gmail account to ALSO check mail on an outside mail server). In most situations, you'll use SMTP over port 25 to exchange mail between servers. (MDaemon supports a feature called "DomainPOP" where you can use Port 110 to collect mail from another server for local distribution based on other headers, but it's not used very often.)
The question sounds like you're trying to SEND email from your local server to an account on Gmail. You'll need to have TCP port 25 open outbound through your firewall to send mail. That doesn't mean that the remote host has to accept mail from you -- but it will make the initial handshake possible.
Usually, a fully configured mail server will have a public IP address and DNS name that directs SMTP traffic to it. It's strongly reccommended that your domain DNS have an MX record that points to your mail server. Ideally, there should be a reverse DNS pointer for the mail server.
Because of all the SPAM in the world, many mail servers refuse connections from other hosts that don't have a DNS record and a reverse pointer. That's not the only reason they refuse connections, of course, but it's one.
Anyways, I expect the original user had one of three possibilities: 1) They needed SMTP open in their firewall when they opened POP instead;
2) They had POP turned off for their MDaemon account (can gmail even be configured to act as a pop client for another account?); or 3) they got blocked because of a bad dns record/pointer combination.

Related

Postfix attempting to bind to port 25, used for outgoing mail only (maybe not necessary?)

Not sure if this belongs on Stack Overflow or somewhere else but I'll try here first.
I have multiple servers, each with the same setup where nearly everything running on the server is in a docker container. I have two goals I would like to achieve. First, the host machine is setup to send emails for users with uid < 1000 to my external email address. Second, on one server, I have a docker-mailserver container running to handle random, seldom used emails (for log files, etc.).
It seems I can have either the host machine running postfix OR the docker-mailserver running (and bound to port 25). Currently, I have the docker container, running the mail server, full operational and everything can send and receive just fine.
However, now I am unable to start postfix on the host machine so that I can receive emails sent to the root user (things like cron output) since port 25 is --rightfully-- in use by the actual mail server receiving email.
Questions:
1) How can I tell postfix on the host to not bind to port 25? If port 25 is only used for receiving mail, why would my outgoing-only postfix config need to use port 25?
2) I am perfectly comfortable not receiving emails for the root user, if whatever would normally be sent to the root user is logged elsewhere (perhaps, syslog?). Are the emails to root only maintained as emails or are they somewhere else, negating the need for postfix on the host for forwarding to a real account?
Thanks in advance.
Specifically answering your questions first:
You should be able to have postfix listen on any port you specify by editing the main.cf configuration file and changing the smtp listener to a numbered port of your choice. Of course, if it isn't a "known" port, I'm not sure what/who will ever connect to it, but maybe you don't care in this situation as you are only using postfix as a relay?
It may depend some on the Linux distribution or setup of your host, but most systems will leave email in the local delivery "mail spool" if there is no system/daemon set up to move it anywhere else. Back when that was the normal way to handle multi-user mail on UNIX systems, a login user used a mail reader client to read through email in your local "spool", and of course if you don't have that, you can simply vi your mail file and read the raw contents if necessary. These mail files are normally located in /var/spool/mail on most systems.
Stepping away from your questions, I would guess you don't necessarily need postfix running on your host, especially as your containerized mailserver is handling the port 25 SMTP traffic for the host. Local email will stay local, I assume, without postfix, and be available through local means; and you might even find a simpler solution to external forwarding (e.g. a script that can parse mail spools and just connect to an SMTP relay and send it to an external address) if you want that.

Port tunneling (other than ssh, e. gr. no-ip)

Network policies at my workplace (a University outside the US) are rather inconsistent. While every port other than 80 and 443 is blocked, no websites are restricted (at least for professors). Gmail/pop and smtp sockets are open as an exception to the rule (which makes both me and the Dean think there is no particular policy against personal e-mail).
I'm faculty at this University, but also teach at a different one, for which I use a university-specific, non-gmail e-mail address. I have all of my e-mail history in Outlook, however, as you can suspect I can access that alternative e-mail address through webmail but not through smtp/pop/imap from my workplace. We asked the sockets to be open but have been given no response by the IT guys in more than a month.
I've been considering port tunneling, but haven't access (right now) to a server with ports 80 and 443 to ssh-tunnel through. I know I could use one port at home to tunnel either the incoming or the outgoing e-mail. But I think it's too power consumming for just half the job.
Is there a way I can do the tunneling with the help of some free service like no-ip, for example?
So far, the best solution I've found is to ssh-tunnel the imap socket. This way, I can get both incoming and outgoing mail through one tunnel. I plan to wake-on-lan and hybernate my home server in order to save power.

which server can host iOS push notification [closed]

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I cannot host my own server for iOS push notification because the router is limited by Admin.
I want to learn from scratch so I don't want to use Parse or quickblox. Where and how can I know which PHP hosting plan support iOS push notification? Is there any free hosting available?
From Apple, the server need to allow inbound and outbound TCP packets over port 2196. I don't think regular hosting plan will list out this information.
http://developer.apple.com/library/ios/#technotes/tn2265/_index.html#//apple_ref/doc/uid/DTS40010376-CH1-TNTAG41
When I learnt Android push notification, I can easily find a hosting plan with CURL. iOS is a bit demanding.
The port that you really need for sending push notifications is 2195. Even though the TCP packets are both inbound and outbound from your server, the connection is only outbound (you initiate the connection to Apple). Most web host providers won't have an issue with this.
Port 2196 is the feedback service, which you should implement, but it's optional. It's the same way, inbound and outbound TCP packets over port 2196, but you initiate the connection.
When a device registers with your server for push notifications by sending the device token, the device initiates the connection, and you have your choice of how to send the notification to the server. If you send it via HTTP (with NSURLConnection, for instance), any basic web server will do.
I implemented Easy APNS in only a couple hours and it works fine on my shared hosting environment at Dreamhost. You just need a basic LAMP stack (Linux, Apache, MySQL, PHP) and a downloaded copy of your APNS certificates. Easy APNS is all open source, so you can see how they're doing it.

unable to send mail when using 3G, but working normally on WIFI [closed]

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I am using Hmailserver as a mail server, and it is working normally for mail clients using a standard internet connection (wired or wireless).
But when using a mobile device in 3G mode, suddenly it is not possible to send emails anymore. In the mail client there is a non saying error message (such as unknown error ocurred). Is there any reason for this?
It is quite hard to say; however, e-mail usually travels over port 25 when using SMTP. Likely your 3G provider is blocking outgoing port 25 connections.
You can verify this by using telnet (a Google for "Windows telnet" will provide some Microsoft documentation) to connect to a well-known mail server (these are advertised in DNS MX records). On Windows, I believe the syntax at the command line would be: "telnet <host> 25" (for Google a valid mail-host is alt2.aspmx.l.google.com).
If your provider is blocking port 25 traffic, you will see a connection denied message. Usually ISP's prefer you connect to their SMTP server -- so that they can prevent SPAM from emanating from their network.

CLOUDFLARE - mail setup [closed]

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I have used Cloudflare for quite a while, but recently, I have bought a mail server with my domain.
I am unsure of how to "root the traffic" through cloudflare - because at the moment, I am unable to receive mail, but I can SEND mail.
I know I need to use MX Records, but I do not know how to get it working.
These are the settings for my mail serve:
Mail Server Username: help#domain.im
Incoming Mail Server: mail.domain.im
Incoming Mail Server: (SSL) mail.au.syrahost.com
Outgoing Mail Server: mail.domain.im (server requires authentication) port 25
Outgoing Mail Server: (SSL) mail.au.syrahost.com (server requires authentication) port 25
Supported Incoming Mail Protocols: POP3, POP3S (SSL/TLS), IMAP, IMAPS (SSL/TLS)
Supported Outgoing Mail Protocols: SMTP, SMTPS (SSL/TLS)
Any help is greatly appreciated. Sorry if I have not explained enough!
If I understand your question correctly you have been using Cloudflare with your website and you are now wondering how to setup your new mail server on Cloudflare.
The mail details you give are for configuring an email client, but what you need are the MX details which are used to specify how to route email for your domain.
To find out MX details start by asking whoever is supplying your mail server.
They typically look something like:
MX priority 10 domain-x
MX priority 20 doman-y
.....
domain-x and domain-y may or may not be the same as your actual website domain.
Once you have the MX details, login to Cloudflare, click the settings icon for the domain and choose DNS settings. Add details of your new MX records and check if there may be outdated MX records there which you need to delete.
Good luck!