All Questions
Tagged with postfix domain-name-system
150
questions
0
votes
0
answers
83
views
Your DKIM signature is not valid - opendkim
I'm running postfix server with few "features" like spf, dmarc and DKIM. SPF and DMARC works fine and when I sent an email to my gmail account I see they PASS, however DKIM shows "FAIL&...
- 101
1
vote
1
answer
586
views
Resolve issues with DNSBLOG and b.barracudacentral.org
I am using postfix with DNSBLOG to prevent spam. The postfix main.cf is configured like:
postscreen_dnsbl_sites =
zen.spamhaus.org=127.0.0.[2..11]*3
b.barracudacentral.org=127.0.0.2*2
DNSBLOG is ...
- 31
0
votes
2
answers
169
views
How can set the order of name servers in LINUX?
This question is in context with the DNS queries by postfix MTA in Ubuntu OS. The issue I am facing is that I have two name servers one internal and one external. External DNS name server is added in ...
- 47
0
votes
1
answer
69
views
Can changing the DNS name of a postfix server damage reputation?
I was tasked with taking charge of all services at my current job after the person previously in charge left. Some of our services were using a domain name that's wholly in his possesion, not that of ...
- 113
-1
votes
1
answer
42
views
Switch MX entry to main domain – Dovecot user issue
I tried switching my MX record from the subdomain mail.mydomain.com to mydomain.com. Updating the Postfix and Dovecot configuration (SSL certs, hostname etc) worked mostly fine. Most e-mail addresses ...
- 267
3
votes
2
answers
791
views
Why does my RSA DANE TLSA work, but my ECDSA DANE TLSA fail?
I've purchased two single domain, wildcard SSL certificates from Namecheap/Sectigo/Comodo. I generated my CSRs in the typical fashion using openssl.
$ openssl req -newkey rsa:4096 -keyout example.com....
1
vote
1
answer
690
views
Can't Receive Email - Postfix iRedMail Server Using Spamhaus & Unbound / BIND9 DNS Servers
iRedMail server configured using ISP's DNS servers. Running several years without issue. Moving from current ISP to Starlink. It appears Starlink uses Cloudflare's public DNS. Currently have both ISPs ...
- 11
1
vote
0
answers
4k
views
Postfix mail server not sending email
I had a postfix server that I had to restore from a backup and deploy onto a new server. Using the new server, the domain name is not allowing me to send email. I am able to receive emails but sending ...
- 13
0
votes
0
answers
36
views
How can I stop mail DNS records from showing my main website? [duplicate]
I’m relatively new to all this, so please bear with me. Most of everything I know is based on guesswork, following tutorials, trial & error…
Anyway, I have a pretty basic LAMP server going on ...
- 1
0
votes
1
answer
1k
views
Postfix and Subdomains
I set up Postfix on an Ubuntu 20.04 machine. However, I am not sure where I have to use the subdomain and where the domain. Let us call them mail.example.com and example.com respectively.
The system ...
- 103
0
votes
0
answers
381
views
postfix not accepting mail from new domain
Okay, so I set this mail server up myself on a virtual private server, and it was working, properly receiving mail from three separate domains (for months). Now though, I've tried adding another ...
- 1
0
votes
2
answers
2k
views
Wouldn't setting the DNS server to 127.0.0.1 prevent my system from actually resolving remote hosts? I found this answer
Wouldn't setting the DNS server to 127.0.0.1 prevent my system from actually resolving remote hosts?
My business email server has the DNS set to the ISP given DNS servers. My Spamassassin is giving ...
- 363
0
votes
1
answer
196
views
Different email addresses of same email server for sending and receiving
I am actually a fresher in terms of configuring an email server.
Recently I configured a Postfix email server combining with dovecot and squirrelmail on AWS EC2 centos server, following this guide:
...
1
vote
1
answer
216
views
Postfix subdomain can send, but not receive external email
I'm setting up an AWS EC2 instance, and I need the server to be able to receive emails. Let's say that I am setting up email on the subdomain mail.myserver.com.
I have Postfix installed, and I can ...
- 363
-1
votes
1
answer
221
views
DNS Records Configuration - Email Going Straight to Spam Box?
I know that in order to hit the inbox, the main DNS records need to be properly set up. These are the main DNS records that every mail delivery system should have for their domain:
TLS
A
MX
DKIM
SPF
...
1
vote
1
answer
426
views
Postfix - NDR messages immediately when sent to a bad domain
We have a service that we offer to one of our clients that sends statements to their clients. Unfortunately, our customer's validation of email addresses isn't always the best, so when they submit a ...
- 15
4
votes
1
answer
406
views
Load balacing email servers: MX vs A/AAAA vs Anycast IP
I'm curious about what are the differences and considerations when implementing email server load balacing between these three methods:
Multiple MX records with the same priority/preference number
...
user578638
0
votes
1
answer
64
views
Postfix: How to reconcile when A record points to outside IP, but hosts file points to 127.0.0.1
Environment: Postfix 3.3, Node.js app, Digital Ocean Droplet
Question: I have a Node.js app that sends email through Postfix. However when it attempts to send it throws a warning.
Warning message:
...
- 599
-3
votes
2
answers
206
views
What are the drawbacks of getting a free domain name [closed]
To configure a server, especially its email services, I'd need several @serverdomainname.topdomain.
I saw it is possible to pick some free domain names that would end in .tk, .ga, .xyz, etc.
I don't ...
0
votes
1
answer
444
views
postfix timeouts on every mail server
I just ran into problem after not enough inodes on a server, which I fixed into this postfix problem. I use
dovecot+amavis+spamassasin+dovecot+postfix
I found this error
postfix/smtpd[1775]: ...
- 207
1
vote
1
answer
301
views
Error sending email (from [email protected] to [email protected] with a response to (reply-to header) to undefined)
I have a Drupal 8 site installed on an Ubuntu 18.04 server with PostFix.
I am able to send and receive emails, but the server cannot send notifications to itself.
The email server address is contact@...
- 11
5
votes
2
answers
4k
views
Postfix in Docker: Host or domain name not found (DNS and Docker)
I'm running Postfix 3.4.8 on Debian 10 (buster) in Docker 19.03.5. Postfix is configured as a smarthost. It relays emails to the SMTP server of our ISP.
If I configure the relayhost setting with the ...
- 199
1
vote
1
answer
2k
views
Postfix - MX: Host not found error but dig and nslookup are OK
I had a working Postfix email server on Centos 7 when I decided to reconfigure my host networking (IP addressing, DNS, etc.), after reconfiguration, mail sending is no longer working.
/var/log/...
- 627
4
votes
2
answers
4k
views
OpenDKIM query timed out (even with opendkim-testkey and Nameservers set)
I try to set up a mail server on Debian with opendkim and opendmarc
When I receive an email, SpamAssassin refuse it because opendkim can't do the DNS query
I tested with opendkim-testkey command, ...
- 61
-1
votes
1
answer
92
views
Email server multiple domain with different IPs
I have 2 domains:
ex1.example with IP 192.0.2.1
ex2.example with IP 203.0.113.2
On ex1.example I installed postfix and dovecot with support working on multiple domains (MariaDB with tables and other ...
- 99
2
votes
1
answer
1k
views
BIND DNS lookup shows a wrong IP for the domain name
I have a BIND DNS server in a LAN with
hostname --short : server
hostname --domain : unisof.com
hostname --fqdn : server.unisof.com
hostname --ip-address : 192.168.1.100
/etc/bind/named.conf....
- 21
0
votes
1
answer
799
views
Postfix warning: dns_get_fixed
I have a recently setup Postfix/Dovecot simple mail server (if there is such a thing).
It was stable, and worked without issue for about 2-3 weeks, until I wanted to get SPF setup. Now, it still ...
- 21
1
vote
1
answer
1k
views
SPF errors when sending emails
I setup a mail server on mail.mydomain.com. I am able to receive email. Problem occurs when i try to send an email. I have two servers:
mail.mydomain.com - which is on different ip (e.g. 1.1.1.1)
...
- 125
3
votes
2
answers
8k
views
Postfix not resolving MX record
Log
to=<[email protected]>, relay=none, delay=21311, delays=21301/0.04/10/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=localdomain type=MX: Host not ...
- 229
0
votes
0
answers
136
views
Supporting multiple domains under one mailserver
I'm running my own Ubuntu server using Postfix to serve my email needs for a certain domain (let's call it domain.com). The mailserver does not have a mailbox, it forwards received emails to assigned ...
- 365
1
vote
0
answers
708
views
Postfix: proper configurations - main.cf, DNS, DKIM
Inherited an Ubuntu server (12.04) running Postfix (2.9.6) that works as an outbound-only mail relay for a web application.
Have got SPF and DMARC records entered in public DNS (Route53). Working to ...
4
votes
3
answers
11k
views
In postfix, what's the difference between myhostname and mydomain?
I'm trying to set up postfix for the first time. Reading the basic configuration docs, right off the bat I'm faced with two settings that I cannot understand - mydomain and myhostname. I've got the ...
- 863
8
votes
2
answers
9k
views
Why does postfix say 'Helo command rejected: Host not found' when dig finds the host?
So I see the following error Helo command rejected: Host not found; in /var/log/syslog, but when I do forward and reverse lookups on the host in question, the DNS records appear reasonable. The mail ...
- 201
0
votes
1
answer
989
views
Which domain should the IP PTR record resolve to?
I am trying to set up a mailserver alongside my webserver, example.com, at IP address 192.0.2.1
I have installed the usual suspects; Postfix, Dovecot, Roundcube,
ClamAV milter, and OpenDKIM. I ...
- 143
0
votes
1
answer
751
views
Postfix doesn't send mails to own domain
I have a problem that my kopano / postfix on ubuntu 18.04 doesn’t send mails to my own domain.
My domain is for example: example.com
I try to send a mail from [email protected] to [email protected]
...
- 31
2
votes
3
answers
4k
views
Are CNAME "imap..." and "smtp..." subdomains needed?
I'm running my Postfix email server. I have only 1 A dns record for it: mail.my_domain.com I'm able to connect to it, receive and send email through it using only this url. Namely, I don't have "smtp.....
- 23
2
votes
1
answer
3k
views
Postfix is looking for /etc/aliases.db for some reason instead of using Postgresql db
I'm trying to setup my Postfix + Devocot + Postgresql. For now just to be able to receive an email, somehow, and save it in the file system.
A part of my postfix/main.cf where I've commented out "...
- 23
0
votes
1
answer
101
views
Cloudflare - Unable to send email
I am unable to send emails after setting up Cloudflare. I have created an A record mail.example.com and an MX record as example.com.
When I receive emails it works just fine, but when the server sends ...
- 113
1
vote
0
answers
713
views
Postfix is unable to resolve IP addresses when running in chroot on Debian Stretch
I was trying to setup my own mailserver and for some reason or another postfix is unable to resolve names or IP addresses when running in chroot. I tested this on a vanilla Debian Stretch/postfix ...
- 221
0
votes
0
answers
612
views
iRedMail - Can't Receive or Send to/from Other Servers
I have just recently installed iRedMail on my fresh install of Ubuntu Server 17.10. The install went fine and I have the servers running as they should.
The issue I am having is the e-mails that I ...
- 228
0
votes
2
answers
575
views
Postfix/Dovecot ++ mail server. Can send mail but not receive mail
Some back story
I have the 3 last days struggled hard to try to get a mail server up and run. After first trying to get it up on a server with blocked ports I decided yesterday after several ...
- 115
0
votes
1
answer
375
views
Reverse DNS issue with Mailserver (Postfix) [duplicate]
My mail server is set to server.mailtuner.com, but when i try sending to a hotmail user, it goes into the spam folder.
Results on mailtester show the following reverse DNS issue: https://www.mail-...
0
votes
1
answer
127
views
Email aliases redirect from example1 to example2 domain
I need to achieve following functionality:
User send email to [email protected] that now is not existing email. I buy this domain (example1.com) and would like auto redirect all emails that ...
0
votes
1
answer
8k
views
postfix - dns error - can't resolve my A or MX record
I've installed postfix on my arch linux pc. I use systemd-resolved and systemd-networkd to establish a network connection.
I want to use postfix as a satellite system to send some mails if my raid ...
- 367
0
votes
1
answer
567
views
How do I create mail.example.com with postfix and dovecot? [closed]
I currently have postfix and dovecot installed on my Ubuntu VPS. While I can log in via a mail client like thunderbird with the IP, it would be nice to have mail.example.com. I already own a domain ...
- 115
1
vote
1
answer
341
views
DKIM check=pass but DomainKeys check=neutral
I got it to set up DKIM, I sent a test mail to [email protected] and reply was :
SPF check: pass
DomainKeys check: neutral
DKIM check: pass
SpamAssassin check: ham
...
- 181
-2
votes
2
answers
549
views
Doesn't receive email from other mail servers [duplicate]
I really need your help. I am trying to set up first time my own mail server using Postfix, Dovecot IMAP/POP3 and MySQL backend on a Ubuntu server. I can successfully receive and send mail to my local ...
0
votes
2
answers
330
views
Some advise needed on how to setup reverse PTR on web and mail server
I'd appreciate some advise on how to run DNS with both httpd and mail running on the same server.
I have one server running on AWS, and i want to run both httpd and mail on it. Currently it just runs ...
- 129
1
vote
0
answers
5k
views
postfix dkim=neutral reason="invalid (public key: missing p= tag)" outgoing email not received
I use postfix to send outgoing emails ... a user does not receive sent posts ... when I sent same to my gmail account post does arrive in inbox ... yet below is what appears on Show Original
...
- 255
0
votes
1
answer
837
views
Setting up a LAN Postfix server with fake domain names
I want to set up a LAN in which several machines can send mail to each-other using a local Postfix server and a local DNS. The machines should be able to use fake domain names ([email protected], etc). ...
- 1