Mail SMTP Relay - Reverse DNS Question
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Hey guys.
This is a personal question for my homelab, nothing business critical, not even always a purpose to what I am doing other than learning and trying out software.
I know there are alternative ways to do something, I'm open to suggestions but ultimately I want to see this one to the end too.So I am trying out something called Artica
I believe I currently have everything configured correctly, (end game is a smtp relay to a different port.)
I currently have mail.domain.ca and I am adding mail-store1.domain.caMail is coming in and being rejected for:
NOQUEUE: reject: RCPT from mail.example.ca[EXAMPLE IP]: 451 4.3.5 : Helo command rejected: Server configuration error; from= to= proto=ESMTP helo=
So looking deeper it looks like its failing on reverse DNS.
So using some google I'm being told to go to where my name server is hosted, so I went to them and got this response:
*Hello,
Reverse DNS is already configured for the shared IP address you are on. If you need a custom rDNS for your domain or such (if that's what they're asking), you would need a dedicated IP address for your site, which we don't do for free.
The current IP has rDNS though, so it shouldn't really be giving you issues. *
I currently have mail.domain.ca working just fine but I would love to get this relay set up, for knowledge, and to try to minimize downtime.
After this I am going to try postfix as well but I would love to get this one up and running.
Anyone have any hints or tips why my reverse DNS wouldnt be working?
I have access to cpanel for whatever DNS or MX changes need to be made.So far I've added an A record and the MX record.
Thanks guys!
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@Sparkum Where is the mail being dropped, incoming to your server, or outgoing to other people's servers?
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@brianlittlejohn
Incoming to the mail relay -
what does it show when you do an nslookup , then put in the ip address of your mail server.
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@brianlittlejohn
On my mail server it brings it up just fine
Or my routing server it says non-existent domain -
@Sparkum Its a reverse DNS issue then. The reverse record should point to the dns name in the EHLO response. Most providers don't give you tools to change reverse dns, they have to do it.
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@brianlittlejohn
Hey.Yep I knew it was a reverse DNS problem, and already contacted my provider.
They said reverse DNS is already configured, already have rDNSSo my question is can I only have reverse DNS on mail.domain or could I have it on mail-store1.domain and if so is there something more I need to do than an A record and a MX record
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I might not have followed this correctly but... PTR (Reverse DNS) records have to be done at the IP Address point, not with your DNS provider. Whoever does your A and MX records can't be the company with the PTR record. Your ISP has to do the PTR record. The ISP at which your MX record points.
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@Sparkum said:
So my question is can I only have reverse DNS on mail.domain or could I have it on mail-store1.domain and if so is there something more I need to do than an A record and a MX record
PTR records are on IP addresses, not on domains. What would a reverse DNS record on a domain even mean?
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@scottalanmiller said:
I might not have followed this correctly but... PTR (Reverse DNS) records have to be done at the IP Address point, not with your DNS provider. Whoever does your A and MX records can't be the company with the PTR record. Your ISP has to do the PTR record. The ISP at which your MX record points.
It is a hosted server, so the host should be the one making sure it is correct.
@scottalanmiller said:
@Sparkum said:
So my question is can I only have reverse DNS on mail.domain or could I have it on mail-store1.domain and if so is there something more I need to do than an A record and a MX record
PTR records are on IP addresses, not on domains. What would a reverse DNS record on a domain even mean?
PTR records on IP Addresses is what he means.
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So here's something weirder....
So apparently last night my email server actually failed to receive emails, error of insufficient resources.
I only noticed this cause I signed up for something and didnt get a confirmation email.
Started looking and ya, my server needed a reboot, but oddly enough Artica was holding onto 15 emails, I rebooted my server, hit resend, and got them all...
I assume I still need to fix the reverse DNS thing though eh?
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@Sparkum I'm still having trouble figuring out what your end goal is. Can you clarify what mail.domain.ca and mail-store1.domain.ca are doing? What you are wanting them to do?
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So mail.domain.ca is simply my email.
Plain and simple thats my email.
Is and has been working for over a year now.mail-store1.domain.ca I simply want to catch emails if for any reason my server fails.
Essentially a baraccuda spam and firewall or other email appliance.Wanting to do it for free, I realize there are services currently out there that do it for a very nominal amount of money.
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@scottalanmiller
Oh really?So I need to contact where the virtual is hosted not where the nameserver is hosted?
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@Sparkum Ok, so you are wanting mail-store1 to store your messages when your mail server is down, then relay them once the mail server is back up.
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@brianlittlejohn
Exactly yup -
@Sparkum Are they both running Artica?
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Nope, Artica is only for the relay
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Then the error you are getting is from messages going from Artica to your mail server correct?
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Honestly at this point I'm a little confused since my mail server did fail last night and Artica 100% did its job.
I guess my real underlying question is getting reverse DNS up and going. If I'm contact who my name server is with or where my virtual is hosted.
And do I simply say "Hey I need a "PTR" record for mail-store1.domain.ca
