I have a Postfix/Dovecot server that is currently rejecting mail where DNS is not configured properly. The sender is getting:
550 5.7.1 Client host rejected: cannot find your hostname
I'm well-aware of the 'spammy' implications, but can someone point me to a resource on where I could figure out how to disable this setting?
I can't seem to locate how to turn it off, and maybe some of you great people here will have an idea.
Thanks
I think I found it. This seems to be the setting I'm looking for:
http://www.postfix.org/postconf.5.html#reject_unknown_client_hostname
disable 'reject_unknown_client_hostname' within /etc/postix/main.cf
Related
I've a full server with mail and web behind a dynamic IP access.
This is all configured to update the ip in case it changes and works well with everything except mail.
Although I've implemented SPF DKIM and DMARK, since the address are listed in PBL, many servers refuse the connection.
I'm trying to solve this issue setting up a relay machine for my domains in a small VPS with Fixed IP and Reverse DNS to avoid PBL's.
I've found a link from a guy that implemented a similar solution, but he changes the sendmail.cf file, that is not supposed to be touched.
This link:
https://www.akadia.com/services/sendmail_relay.html
How can I do this in the sendmail.mc file for compilation with m4?
My idea is to set the mx records pointing to this vps acting as relay, and also configure my postfix mailserver to forward mail to the relay, which I think I've found were to do this in webmin.
Hope someone can shed some light in my head.
Thanks in advance.
You can specify default relay for outgoing email in sendmail.mc file using SMART_HOST.
define(`SMART_HOST', `name.of.smart.host')dnl
Useful tip: You may put smart host name in square brackets to avoid lookup for DNS MX records.
define(`SMART_HOST', `[name.of.smart.host]')dnl
WARNING
sendmail uses *.cf files as configuration. *.mc fIle must be "compiled" into *.cf file.
I am seeing the via centsol.com in some one's mail who has no access to centsol smtp server. I googled it and found that this issue is related to "Open relay" function of smtp. So my question is how to resolve this issue?
Well it really depends on what system you're using for sending mail.
Exchange Server: http://www.techrepublic.com/article/prevent-open-relays-on-exchange-server/
If you're using postfix or something else, the fix could be a lot more complicated than that.
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.
I would like like guidance regarding an issue we are having on our CentOS server.
Just recently we noticed that we cannot send emails to Hotmail.com mailboxes from our domain email. I also discovered that we're getting a lot of mail delivery failure emails in one of the inbox's that we don't use.
I've checked the mail logs and saw some suspicious activity. Unfortunately, I don't know much with regards to mail server and how they behave. Can someone shine some light on this situation and tell me if some is connecting to our SMTP server remotely and sending spam emails to various recipients? What other steps should I take to prevent this?
Here is part of the log:
2013-06-09 05:43:27 SMTP connection from [110.52.1.237]:13088 (TCP/IP connection count = 1)
2013-06-09 05:43:32 no host name found for IP address 110.52.1.237
2013-06-09 05:43:41 SMTP connection from [110.52.1.237]:13461 (TCP/IP connection count = 2)
2013-06-09 05:43:46 no host name found for IP address 110.52.1.237
2013-06-09 05:43:46 unexpected disconnection while reading SMTP command from (iem.net) [110.52.1.237]:13088
2013-06-09 05:43:55 H=(qbnngj.com) [110.52.1.237]:13461 sender verify fail for <wqnsjzyyc#qbnngj.com>: The mail server could not deliver mail to wqnsjzyyc#qbnngj.com. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.
2013-06-09 05:43:55 H=(qbnngj.com) [110.52.1.237]:13461 F=<wqnsjzyyc#qbnngj.com> rejected RCPT <support#greenXXXX.com>: Sender verify failed
2013-06-09 05:43:55 unexpected disconnection while reading SMTP command from (qbnngj.com) [110.52.1.237]:13461
As you can see above, the IP that connected to the SMTP server is from China. I have a dozen of similar connections made in the log.
I am not sure how to resolve this issue.
Any help would be appreciated.
Thank you,
Max
You have two separate problems.
Sending to Hotmail: They have a web page regarding their own private white list, and if you're not on the list, you get blocked.
Receiving delivery status notices for messages not sent: Someone is spoofing your domain in messages they're sending to others. You need to protect your domain with some authentication technology. The two most common are called "sender policy framework" and domainkeys.
I have a 1&1 VPS with Plesk, and a domain name with 123-Reg. I've configured my DNS records as such:
www a 87.106.101.240
mail a 87.106.101.240
mail.limehousecraftsandgifts.com. mx 10
From within Plesk, on the limehousecraftsandgifts.com domain, I've got a mail redirect for all email to go to my Gmail. But the emails are not getting through.
Does anyone know what I'm doing wrong? 87.106.101.240 is my server.
Thanks,
Steven
For one thing, you don't have an A RECORD for mail.limehouecraftsandgifts.com =)
You should point it where-ever you want the mail delivered.
Thanks to Shad, I was able to investigate and realise that my DNS settings were correct. I was having a problem with Qmail on my VPS. The command line for Qmail said it was running fine, but the Plesk control panel would allow the service to start, but would then stop 20 seconds later. Ultimately, the problem was a misconfigured Qmail. So check your mail logs, and your Qmail status if you're having this problem.
I'm leaving this here as a note to anyone encountering similar issues.