How do you find the IP address of a specific mail server? - email

For example, how can I find the IP address of the mail server #yahoo.com or #hotmail.com?
Is there a way to do this on terminal?
Thank you.
EDIT: I meant to say IP address of the mail server dealing email addresses ending with #yahoo.com or #hotmail.com

nslookup is what you're after, or dig. Since you want a mail server you'll want to add the option '-type=mx' (Mail eXchange).
nslookup -type=mx gmail.com

First find the mailserver (might be multiples):
dig yahoo.com mx
Then request the IPv4 record:
dig <yahoo-mx> a
In some cases you can find the IP inside the SPF record:
dig <yahoo-mx> txt

Related

Is smtp.gmail.com the same sending IP for everyone?

I use Google Workspace to send emails. Is the IP address I see when pinging smtp.gmail.com the same IP as everyone else?
Secondly, does this IP address ever change?

Can I run an email Server with a fixed IP only?

I created a web app to do some basic content management for just myself. I want to mail some docs to the server instead of downloading then uploading them. Ive been looking at postfix but everything assumes you have a domain. Is it possible to receive email at a server with a fixed ip and no domain?
if you want anybody and any app to be able to send mail you need MX records in DNS. And MX records point at dns server names, not IP addresses.
https://serverfault.com/questions/663112/why-cant-mx-records-point-to-an-ip-address
If its just you then you can telnet to the SMTP port to send mail

How can I setup reverse DNS for a home SMTP server?

I am running Postfix MTA on my home server to send bulk emails.I have setup MX records and DNS but rDNS still needs to be configured as gmail etc. won't accept email from my IP. I don't have a VPS so I can't use cPanel or WHM. Is there any other alternative.
NOTE: I can't use a mail provider like gmail as I need to send more than 500 emails daily.
Thanks a lot!
Reverse IP address is linked with the PTR record set by the owner of the IP address which is mostly your ISP. You need to check with your ISP (Internet Service Provider) on updating the PTR record for the IP address assigned to you.

Postfix: loops back to myself error

I've been trying to install a Postfix server for handling mail for my domain. I found some nice tutorial and I was able to create email address and server responds correctly with telnet (imap and pop3 included, I also charge the config in Gmail and works correctly).
To handle POP3 and IMAP I have installed Courier
The problem comes when I try to send e-mails to myself (with external email address), I receive the following error code:
Action: failed
Status: 5.4.6
Diagnostic-Code: X-Postfix; mail for (servername) loops back to
myself
I reviewed my postfix mail.conf config, as in many webs they said that it could be because mydestination was not corectly configured. I have included the domain configuration and I still get the same error. (/etc/postfix/main.cf)
mydestination = mail.mydomain.com, domain.com, localhost
This is in a VPS, so the hostname is different to the domain name, I'm not sure if this can have any influence on the handling mail error.
Could someone help me to find where can the error be?
Thanks for your attention and your answers
You're probably sending mail to a recipient, with an email address in a zone which has an MX record, with its value a hostname, which resolves to the ip address of your mailserver, while this your server hasn't been told in its main.cf config file (behind mydestination), that it is referring to itself.
Therefore, your server is wondering why an attempt to send mail to - as it believes - another server results in finding that the ip address of that another server is its own ip address.
Update mydestination accordingly.
It helps to use the same hostname for MX record, for all zones your mailserver handles incoming mail for, as that keeps your mydestination manageable.

How to properly set up DNS SPF records for a .local server?

We send out mail via Microsoft Exchange 2010 running on a Windows Server set up as server.organization.local.
When error messages are generated it shows:
Generating server: server.organization.local
I am confused as to what our SPF records should look like based on this. Should it simply contain the external IP address that this server uses to send out mail, or both this .local address and external IP address?
Currently it is set as:
# 10800 IN SPF "v=spf1 mx a:server.organization.local ip4:10.10.10.10 -all"
The mx is included to be safe but I'm not sure if it needs to be? The MX records on the domain name is set to a third-party filtering service, no mail is sent via it.
You need to specify the public IPs if you want to send emails to the internet.
If you are sending emails to another mail server on the LAN then you might have to add the private IPs as well.
I suggest to use a testing utility to check your SPF records.