i'm new as a Admin and this is an small office with around 15 employees.
we had installed a opensource mailserver(Zimbra) in our local server and it works perfectly on local. & we have registered our domain in bigrock.
I have to make it works on Internet.
I had added the MX Record, A record and TXT record in bigrock and it works on internet. Kindly address me to add txt record, and proper way to map things and all!!
Whenever i logon to the mailserver it shows, Unsecured connection. How to solve this kind of errors?
And Most of the time our domain got blacklisted in (spamhaus or mxtoolbox site - On UCEPROTECTL1, On UCEPROTECTL3, On protected sky) i dont know why it happens more often? (We dont send bulk emails. overall we send around 400 emails per week.) Due to this blacklisting, our outgoing has been strucked and all our outgoing mails are bouncing back. but still we can able to receive mails. Kindly address this issue!!!?
And Partially some of the domains cant able to receive mails from our domain. net4india spamfilter blocking our mails(one of our client having spamfilter in net4. they didnt receive our mails and we dont even get any bounce mails) and recently one of our client having email in net4india and he did not able to receive mails from our mail server and the error shown in postfix is pasted below,
Mar 2 17:10:37 rytweb postfix/pickup[15292]: 342AA2C1EC4: uid=48 from= Mar 2 17:10:37 rytweb postfix/cleanup[15603]: 342AA2C1EC4: message-id=<20160302114037.342AA2C1EC4@rytweb.ourdomain.in> Mar 2 17:10:37 rytweb postfix/qmgr[15293]: 342AA2C1EC4: from=, size=575, nrcpt=1 (queue active) Mar 2 17:10:46 rytweb postfix/smtp[15607]: 342AA2C1EC4: to=, relay=mail.net4india.com[118.67.248.42]:25, delay=8.9, delays=0.21/0.02/0.15/8.5, dsn=5.0.0, status=bounced (host mail.net4india.com[118.67.248.42] said: 550-Verification failed for 550-Unrouteable address 550 Sender verify failed (in reply to RCPT TO command)) Mar 2 17:10:46 rytweb postfix/cleanup[15603]: 0DDC12C1EC5: message-id=<20160302114046.0DDC12C1EC5@rytweb.ourdomain.in> Mar 2 17:10:46 rytweb postfix/qmgr[15293]: 0DDC12C1EC5: from=<>, size=2659, nrcpt=1 (queue active) Mar 2 17:10:46 rytweb postfix/bounce[15611]: 342AA2C1EC4: sender non-delivery notification: 0DDC12C1EC5 Mar 2 17:10:46 rytweb postfix/qmgr[15293]: 342AA2C1EC4: removed Mar 2 17:10:46 rytweb postfix/local[15615]: 0DDC12C1EC5: to=, orig_to=, relay=local, delay=0.13, delays=0.05/0.02/0/0.05, dsn=2.0.0, status=sent (delivered to mailbox) Mar 2 17:10:46 rytweb postfix/qmgr[15293]: 0DDC12C1EC5: removed
How to solve this problems?
In order to secure your mail server you need to run it under SSL - Which is https:\mail.yourdomain.com
Once you have SSL Setup you can still have vulnerabilities - which can be tested with pen-tools or ssllabs. You can also do run a detail mail port check using this tool: Email Authentication and Configuration Tester
The reason you can be having blacklist issues is maybe your mail server is an open-relay? You should test that as well: Open Relay Tester
You also need to add SPF, DKIM, and follow a slew of other RFC's to ensure your email is set up properly, if you haven't already. It's also good to monitor your domain for Blacklists, I use Unlock The Inbox Blacklist Monitor since they package a bunch of tools together, but there are many good options available.
You're not going to get everything perfect in a day, don't get frustrated. You have to isolate the issues and deal with them one at a time.