Not receiving mail

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picho
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Not receiving mail

Post by picho » 2019-06-07 08:27

Dear Team,

I am having trouble with my hmailserver,

Last week i had my domain hosting provider transferred to another host and since then, i have been receiving fewer mails than usual with many mails not being received by my email accounts.

I have restarted the server.

I now don't know what to do, how can i find out what is wrong with my system.

I will be glad for your assistance,

regards,

Picho

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nitro
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Re: Not receiving mail

Post by nitro » 2019-06-07 09:09

I would start with the simplest:
- Is it the same IP address?

- Can you make a telnet connection to port 25?
It is common for hosting providers to disable port 25.

Use this diagnostic tool.

https://mxtoolbox.com/diagnostic.aspx
Production 5.6.8-B2437.20_OpenSSL_1.0.2s W.Server 2016 Datace [2x Intel Xeon E5-2660 8GB RAM]
Staging 5.7.0-B2428-LibreSSL-x64-LTS W.Server 2008 R2 Stand [Intel Pentium 4 4GB RAM]

picho
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Re: Not receiving mail

Post by picho » 2019-06-07 09:47

Thank u Nitro for your response.

I used the tool from the link and below are the results from the tool:

Test Result
SMTP Banner Check Reverse DNS does not match SMTP banner
SMTP TLS Warning - does not support TLS
SMTP Server Disconnected May be an open relay
SMTP Reverse DNS mismatch OK X.X.X.X resolves to X.X.X.X
SMTP Valid hostname Ok Reverse DNS is a valid hostname

it then says you hung up on us after we connected. Please whitelist us (connection lost)


what could be the problem ?

picho
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Re: Not receiving mail

Post by picho » 2019-06-07 09:51

when i run diagnostics on the hmailserver utility, it resolves perfectly to mail.hmailserver.com without any errors

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nitro
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Re: Not receiving mail

Post by nitro » 2019-06-07 12:06

SMTP Banner Check Reverse DNS does not match SMTP banner <- Bad HELO

SMTP Server Disconnected May be an open relay

https://www.hmailserver.com/documentati ... elay_tests


My server:

SMTP Reverse DNS Mismatch OK - 1.1.1.1 resolves to mail.domain.es
SMTP Valid Hostname OK - Reverse DNS is a valid Hostname
SMTP Connection Time 0 seconds - Good on Connection time
SMTP Open Relay OK - Not an open relay.

It is important to know if the IP has changed.
If you have changed, you should analyze if the DNS is changed and if it has propagated correctly.

https://www.whatsmydns.net/
Production 5.6.8-B2437.20_OpenSSL_1.0.2s W.Server 2016 Datace [2x Intel Xeon E5-2660 8GB RAM]
Staging 5.7.0-B2428-LibreSSL-x64-LTS W.Server 2008 R2 Stand [Intel Pentium 4 4GB RAM]

palinka
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Re: Not receiving mail

Post by palinka » 2019-06-07 12:59

nitro wrote:
2019-06-07 12:06
SMTP Banner Check Reverse DNS does not match SMTP banner <- Bad HELO
Not necessarily. I recently learned that PTR resolves to an FQDN that your ISP has assigned to you. Checking PTR wil tell you for sure. The fix is to ask your ISP to update their DNS to reflect your mx FQDN.

For example, I'm on a dynamic residential ip. I cannot ask my ISP to update anything because of that but it makes a good example despite that.

My helo banner: mail.domain.com
My mx record: mail.domain.com
My ip: 12.34.56.78
PTR checks IP which resolves to pool-12-34-56-78.nycmny.fios.verizon.net
No match.

Doesn't affect me because i use a relay and receiving servers check reverse dns against the relay and not my ip.

I hope i got all that right. :mrgreen:

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nitro
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Re: Not receiving mail

Post by nitro » 2019-06-07 13:05

palinka wrote:
2019-06-07 12:59
nitro wrote:
2019-06-07 12:06
SMTP Banner Check Reverse DNS does not match SMTP banner <- Bad HELO
Not necessarily. I recently learned that PTR resolves to an FQDN that your ISP has assigned to you. Checking PTR wil tell you for sure. The fix is to ask your ISP to update their DNS to reflect your mx FQDN.

For example, I'm on a dynamic residential ip. I cannot ask my ISP to update anything because of that but it makes a good example despite that.

My helo banner: mail.domain.com
My mx record: mail.domain.com
My ip: 12.34.56.78
PTR checks IP which resolves to pool-12-34-56-78.nycmny.fios.verizon.net
No match.

Doesn't affect me because i use a relay and receiving servers check reverse dns against the relay and not my ip.

I hope i got all that right. :mrgreen:

For my server +2 in the spam score :twisted:
Production 5.6.8-B2437.20_OpenSSL_1.0.2s W.Server 2016 Datace [2x Intel Xeon E5-2660 8GB RAM]
Staging 5.7.0-B2428-LibreSSL-x64-LTS W.Server 2008 R2 Stand [Intel Pentium 4 4GB RAM]

palinka
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Re: Not receiving mail

Post by palinka » 2019-06-07 13:36

nitro wrote:
2019-06-07 13:05
For my server +2 in the spam score :twisted:
Me too. Plus i noticed that a lot of bot spam comes in on residential IPs with FQDN in helo as i showed for mine. They pass reverse DNS check. So i check helo for IP matches within the helo. If there's a match, i reject. "Real" mail servers don't have helo banners that look like a residential ip PTR. :mrgreen:

picho
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Re: Not receiving mail

Post by picho » 2019-06-07 18:11

Hi Nitro i ran the diagnostic test using DNSGoodies.com the open relay test is taking too long, what should i do to configure on my hmailserver

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Re: Not receiving mail

Post by picho » 2019-06-07 18:11

actually the open relay test aborted

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mattg
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Re: Not receiving mail

Post by mattg » 2019-06-09 01:23

picho wrote:
2019-06-07 09:47
Thank u Nitro for your response.

I used the tool from the link and below are the results from the tool:

Test Result
SMTP Banner Check Reverse DNS does not match SMTP banner
SMTP TLS Warning - does not support TLS
SMTP Server Disconnected May be an open relay
SMTP Reverse DNS mismatch OK X.X.X.X resolves to X.X.X.X
SMTP Valid hostname Ok Reverse DNS is a valid hostname

it then says you hung up on us after we connected. Please whitelist us (connection lost)


what could be the problem ?
Enable all logging in hMailserver and repeat the above test, and the show ALL logs created, and the exact (screen shot) error message that you receive.

Also show the results of these diagnostics >> viewtopic.php?f=20&t=30914
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

picho
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Re: Not receiving mail

Post by picho » 2019-06-10 11:47

thank you members for all your support,

i realised the culprit was auto ban, because of attempts by spammers to hijack our systems, hmail would trigger autoban after 3 failed logon attempts and it would autoban our gateway ip address and so that kept us from receiving mail until the ban would be lifted and soon after it would autoban again.

so what i did, i disabled autoban, i have also configured antispam settings on our firewall to handle spam coming into our network, also i have enabled intrusion protection and intrusion detection.

My system is running smoothly, what a relief for me, i almost gave up on hmailserver :P :D :D :D

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mattg
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Re: Not receiving mail

Post by mattg » 2019-06-10 12:34

Why your gateway IP address?
It obviously isn't NATting, and is likely doing some mail inspection.
This also means that you probably can't do SSL or StartTLS connections

There may be a security issue there (despite the intent).
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

picho
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Re: Not receiving mail

Post by picho » 2019-06-10 13:26

yes my gateway ip address is on the firewall and it does mail inspection, intrusion detection

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mattg
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Re: Not receiving mail

Post by mattg » 2019-06-10 23:35

mattg wrote:
2019-06-10 12:34
you probably can't do SSL or StartTLS connections

There may be a security issue there (despite the intent).
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

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