What is the Gmail MX server port? - email

I know that the Gmail MX (Mail Exchanger) server is at gmail-smtp-in.l.google.com, but I can't find the port.
Port 25 worked for me earlier, but now it seems to have broken. Every time I try to connect, the connection times out. Is there a TLS/SSL port that I could use instead?
Also, is there a default TLS/SSL port for all MX servers?

According to https://productforums.google.com/forum/#!topic/gmail/lJZECWhPBFM, I am probably not able to connect due to a lack of a DNS address.
Thanks to everyone for helping me get to that realization.

It is 587(TLS), and 465(SSL). You can take a look at the google document.

Related

How to find out what SMTP port you are using?

How do i find out what SMTP port the corporation i work for has set up for it's email server?
I've tried searching for it via outlook but it doesn't give me the option.
I'm looking for an answer that i'll be able to do via cmd.
Posting this question here so future individuals who are in my position will know what to do
The default SMTP port for most mail servers is port 25; either that or port 587 if you are using explicit SSL. If you are using implicit SSL, then it is port 465. You should be able to discover the port through Outlook; here is an article: https://www.doteasy.com/domain-email-and-website-hosting-articles/how-to-update-your-smtp-port-ssl-settings-and-smtp-authentication
If like me you work for a large company, the issue is that IT are blocking the ports. You need to go and have a word with the IT department to get it fixed.

Configure CSF to allow outbound SMTP

I have a web app that sends email via SMTP (Gmail, Zoho Mail servers). The thing is, the email sending works in my localhost but not on my VPS (using WHM).
I contacted support and the guy replied:
If your VPS has ConfigServer Firewall (CSF) installed then this would
most likely be causing the problem. As it is working on localhost but
not externally this certainly sounds like it might be the case. You
will need to review the firewall configuration on the VPS and ensure
hose ports are allowed outbound.
But when it comes to server management and configuration, I'm totally lost. I did check the CSF settings page on WHM but not sure where to start.
Any recommendation or solution would be appreciated.
You have to allow outgoing traffic to ports 25, 465, 587 and in the case of Mandrill 2525 as will. You should actually be fine enabling only the one you will connect to. So:
sudo vim /etc/csf/csf.conf
add 25,2525,465,587 to TCP_OUT, and to TCP6_OUT if you use IPv6.
You might also need to remove that ports from SMTP_PORTS if you have SMTP_BLOCK enabled (if it is set to 1).
Source: https://community.centminmod.com/threads/csf-firewall-info.25/#post-6613

Is it possible to see connection attempts to a Google Cloud SQL instance?

We are currently encountering the following error when trying to connect to a Cloud SQL instance: Lost connection to MySQL server at 'reading initial communication packet', system error: 0.
This is a familiar error, and as detailed here usually means the IP address needs to be whitelisted. However, we believe we have done so.
Is there a way to see connection attempts and their IP addresses that have been made (and refused) to the Cloud SQL instance?
Currently we don't expose that information but it is something we would like fix. :-)
According to #Razvan, as of September 2014, this information isn't exposed.
We ended up using CIDR blocks to search the space and find the actual IP address. This is unsatisfying, obviously, but it's a way to pin down the problem.
If other people want to sanity check that the problem is their IP is being refused, you can add 0.0.0.0/0 in order to accept all ranges and try to connect. If it works, you know what is the problem.
Be absolutely sure to remove this as an accepted range, after you are done, however!
Figured I might help someone who stumbles here.
Had exactly the same issue essentially trying to connect to a GCP SQL instance from a hosting provider.
Whitelist the IP address that is shown in my cpanel and it will not connect. (It used to, but the provider made some changes with their infrastructure lately and it stopped working)
put 0.0.0.0/0 in my Cloud Platform whitelist and it connects no problem.
So now I know that my cpanel IP is not the IP trying to connect to GCP.
After some hair pulling (figured that the bare metal server had a different IP than my cpanel IP, it did, but this also didn't work.)
finally tried the IP address for the name servers that point to my domain and bam. All is good.
If you are facing this issue, try your name server (usually something like NS1.hostingprovider.com etc..). I put both the NS1 and NS2 ip's in the whitelist and we are working fine.

Mail not getting send to specific domains

We have a VPS with CentOS combined with DirectAdmin which we use for a Magento shop. This runs fine, except for sending email.
Problem:
It appears that some specific domains won't receive our emails and we get a bounce. If we use any other email sending systems, the mails arrive without problems.
The bounce mail contains the following error:
SMTP error from remote mail server after HELO Company-Shops:
host mx-cluster-b2.one.com [IP ADRESS]: 504 5.5.2 :
Helo command rejected: need fully-qualified hostname
After googling and trying things for a week now, I am a bit lost. I tried checking postfix in CentOS, but this is not installed and I'm not quite sure if this is needed.
Possible issue?
I believe the hostfile in CentOS is setup incorrectly:
127.0.0.1 localhost localhost.localdomain localhost4 ... etc
OUR IP Company-Shops
'Company-Shops' should probably be a domain name, am I right? The same as the rDNS. But I'm afraid if I change this it will kill my site and whatnot. I'm not sure if this entry correlates with the 'company-Shops' helo label in the bounce error.
Some extra info:
- We use the webmail Roundcube from DirectAdmin
- At the moment we run one shop, but this might grow a bit (multiple sites on 1 IP)
- We don't use subdomains
- We've set up a reverse DNS, with the domain
Is there anyone with similiar experiences or with a bit more knowledge about this subject? I appreciate any advice we can get, as we are stuck..
Many thanks.
Yes, that's right: your mail server should identify itself using a fully-qualified domain name when it connects to send mail via SMTP. You don't say what mail server you're running, but since you're using DA, it's probably Exim. If so, you want to edit /etc/exim.conf and set primary_hostname to the FQDN of your server.
This would also be a good time to double-check that reverse DNS is set up properly for your IP address. Many hosts will also reject email from servers on IPs without a valid rDNS record.
I'm not familiar with Magento, but I can't see any way that changing the Exim configuration in this way could impact that program.

Receiving email with Amazon EC2?

I have no trouble sending out email with my EC2 server, but how can I check the email that is sent to me? I have an elastic IP setup and modified reverse DNS records. Do I need to install Postfix to receive email?
Ensure that port 25 is active and open on your server. Install an SMTP service on your instance ...postfix is mighty fine.
Ensure you have also set up some MX records if you want to receive email from the world...
I suppose the first thing to do is testing if you can open a telnet connection to port 25 on your server. Then you know if anything is listening for incoming mail.
If not, then you should probably install postfix as well as test your firewall settings (I seem to recall the EC2 having some sort of firewall setting for which ports to allow in the web interface)
edit: correct port number