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Problem with username with "prvs="
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Hello
I'm having problems sending mail from Mdaemon to my Internet mail provider's SMTP server. In smtp sessions, Mdaemon is putting the text “prvs=xxxxxxx=” in front of the username, as a result the smtp server rejects the connection because it is a non-existent user in the system.
For example, if the user is user@mydomain.com, Mdaemon is using “prvs=45784538972=user@mydomain.com” so the SMTP server rejects that user.
I use Mdaemon 24.0.2.
I had noticed that prior to this release, Mdaemon would append that initial part to the username when using the smart host, but now it seems to always use it.
How do I stop Mdaemon from adding that text to the From of the smtp session?
Thanks
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Arron Staff
SMTP servers rejecting messages because of the prvs= value used in the MAIL FROM value indicates that the SMTP server you are sending to does not support Backscatter Protection (BATV). You can adjust the settings in MDaemon by going to Security | Other | Backscatter Protection.
I'd also reccomend contacting your ISP and requesting that they add support.
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Hello Arron
I've except for Backscatter Protection the IP of Smtp Server, and it works fine.
Thank you very much
Thanks also for your reccomend about my ISP, I'll tell about this.
Best regards
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Hello Arron
Unluckily, today fail again when Mdaemon send mails via smart host.
I've checked the IP and name of smart host in the logs of the smtp sessions and both of them are included in the exemptions of Backscatter Protection.
Also, I've checked are the same IP as yesterday, when it worked.
I've also included, in CIDR format, the subnet of smart host. But it doesn't work.
Thanks
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Arron Staff
Please post the logs from MDaemon that show MDaemon receiving the message and the outbound SMTP log that shows MDaemon attempting to deliver the message.
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Hello Arron
Here the SMTP log of a fail send of today:
[01998029] Attempting to send message to smart host
[01998029] Attempting SMTP connection to smtp.serviciodecorreo.es
[01998029] Resolving A record for smtp.serviciodecorreo.es (DNS Server: 192.168.23.26)...
[01998029] * D=smtp.serviciodecorreo.es TTL=(39) A=[82.223.190.139]
[01998029] Attempting SMTP connection to 82.223.190.139:465
[01998029] Waiting for socket connection...
[01998029] * Connection established 192.168.23.21:61691 --> 82.223.190.139:465
[01998029] Waiting for protocol to start...
[01998029] Negociación SSL exitosa (TLS 1.2, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256)
[01998029] El certificado SSL es válido (coincide smtp.serviciodecorreo.es y está firmado por una CA reconocida).
[01998029] <-- 220 smtp.serviciodecorreo.es ESMTP ready
[01998029] --> EHLO myserver.mydomain.es
[01998029] <-- 250-smtp.serviciodecorreo.es
[01998029] <-- 250-PIPELINING
[01998029] <-- 250-SIZE 51200000
[01998029] <-- 250-ETRN
[01998029] <-- 250-ENHANCEDSTATUSCODES
[01998029] <-- 250-8BITMIME
[01998029] <-- 250 AUTH PLAIN LOGIN
[01998029] --> AUTH LOGIN
[01998029] <-- 334 ------------------------
[01998029] --> **********
[01998029] <-- 334 ------------------------
[01998029] --> **********
[01998029] <-- 235 2.0.0 OK
[01998029] --> MAIL From:<prvs=198264c7e2=user@mydomain.es> SIZE=6743
[01998029] --> RCPT To:<xxxxxxxxxx@berger-levrault.com>
[01998029] --> DATA
[01998029] <-- 250 2.1.0 Ok
[01998029] <-- 553 5.7.1 <prvs=198264c7e2=user@mydomain.es>: Sender address rejected: not owned by user user@mydomain.es
[01998029] --> QUITThe log of yesterday when it worked is:
Thu 2024-09-19 20:49:16.842: 05: [01997381] Attempting to send message to smart host
Thu 2024-09-19 20:49:16.842: 05: [01997381] Attempting SMTP connection to smtp.serviciodecorreo.es
Thu 2024-09-19 20:49:16.842: 05: [01997381] Resolving A record for smtp.serviciodecorreo.es (DNS Server: 192.168.23.26)...
Thu 2024-09-19 20:49:16.844: 05: [01997381] * D=smtp.serviciodecorreo.es TTL=(14) A=[82.223.190.139]
Thu 2024-09-19 20:49:16.844: 05: [01997381] Attempting SMTP connection to 82.223.190.139:465
Thu 2024-09-19 20:49:16.845: 05: [01997381] Waiting for socket connection...
Thu 2024-09-19 20:49:16.866: 05: [01997381] * Connection established 192.168.23.21:65390 --> 82.223.190.139:465
Thu 2024-09-19 20:49:16.866: 05: [01997381] Waiting for protocol to start...
Thu 2024-09-19 20:49:16.914: 01: [01997381] Negociación SSL exitosa (TLS 1.2, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256)
Thu 2024-09-19 20:49:16.976: 01: [01997381] El certificado SSL es válido (coincide smtp.serviciodecorreo.es y está firmado por una CA reconocida).
Thu 2024-09-19 20:49:17.141: 02: [01997381] <-- 220 smtp.serviciodecorreo.es ESMTP ready
Thu 2024-09-19 20:49:17.141: 03: [01997381] --> EHLO myserver.mydomain.es
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250-smtp.serviciodecorreo.es
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250-PIPELINING
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250-SIZE 51200000
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250-ETRN
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250-ENHANCEDSTATUSCODES
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250-8BITMIME
Thu 2024-09-19 20:49:17.163: 02: [01997381] <-- 250 AUTH PLAIN LOGIN
Thu 2024-09-19 20:49:17.163: 03: [01997381] --> AUTH LOGIN
Thu 2024-09-19 20:49:17.185: 02: [01997381] <-- 334 -----------------------------
Thu 2024-09-19 20:49:17.185: 03: [01997381] --> **********
Thu 2024-09-19 20:49:17.210: 02: [01997381] <-- 334 -----------------------------
Thu 2024-09-19 20:49:17.210: 03: [01997381] --> **********
Thu 2024-09-19 20:49:17.234: 02: [01997381] <-- 235 2.0.0 OK
Thu 2024-09-19 20:49:17.234: 03: [01997381] --> MAIL From:<user@mydomain.es> SIZE=91618
Thu 2024-09-19 20:49:17.234: 03: [01997381] --> RCPT To:<other.user@domain.es>
Thu 2024-09-19 20:49:17.234: 03: [01997381] --> DATA
Thu 2024-09-19 20:49:17.277: 02: [01997381] <-- 250 2.1.0 Ok
Thu 2024-09-19 20:49:17.277: 02: [01997381] <-- 250 2.1.5 Ok
Thu 2024-09-19 20:49:17.277: 02: [01997381] <-- 354 End data with <CR><LF>.<CR><LF>
Thu 2024-09-19 20:49:17.277: 01: [01997381] Sending <c:\mdaemon\queues\remote\pd1001000203071.msg> to [82.223.190.139]
Thu 2024-09-19 20:49:18.763: 01: [01997381] Transfer Complete
Thu 2024-09-19 20:49:18.798: 02: [01997381] <-- 250 2.0.0 Ok: queued as 4X8l192K4gz3hnlP
Thu 2024-09-19 20:49:18.799: 03: [01997381] --> QUIT
Thu 2024-09-19 20:49:18.821: 02: [01997381] <-- 221 2.0.0 Bye
Thu 2024-09-19 20:49:18.821: 01: [01997381] SMTP session successful (Bytes in/out: 8504/188987)
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Arron Staff
Can you post the log from the inbound SMTP session that shows the message being received?
Was the message received from an IP address that was excluded from BackScatter?
Was the MAIL FROM value alredy BATV encoded when MDaemon received the message?
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Hello
The log of inbound SMTP session is the next:
Fri 2024-09-20 13:56:47.305: 05: [01998028] Session 01998028; child 0001
Fri 2024-09-20 13:56:47.305: 05: [01998028] Accepting SMTP connection from 192.168.23.27:58056 to 192.168.23.21:587
Fri 2024-09-20 13:56:47.308: 03: [01998028] --> 220 myserver.mydomain.es ESMTP MSA Fri, 20 Sep 2024 13:56:47 +0200
Fri 2024-09-20 13:56:47.838: 02: [01998028] <-- EHLO [10.104.1.100]
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-correo.aytocuellar.es Hello [10.104.1.100] [192.168.23.27], pleased to meet you
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-VRFY
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-EXPN
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-8BITMIME
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-ENHANCEDSTATUSCODES
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-PIPELINING
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-CHUNKING
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250-STARTTLS
Fri 2024-09-20 13:56:47.838: 03: [01998028] --> 250 SIZE 51200000
Fri 2024-09-20 13:56:47.941: 02: [01998028] <-- STARTTLS
Fri 2024-09-20 13:56:47.941: 03: [01998028] --> 220 2.7.0 Ready to start TLS
Fri 2024-09-20 13:56:48.017: 01: [01998028] Negociación SSL exitosa (TLS 1.2, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P256)
Fri 2024-09-20 13:56:48.029: 02: [01998028] <-- EHLO [10.104.1.100]
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-myserver.mydomain.es Hello [10.104.1.100] [192.168.23.27], pleased to meet you
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-VRFY
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-EXPN
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-AUTH LOGIN CRAM-MD5 PLAIN
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-8BITMIME
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-ENHANCEDSTATUSCODES
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-PIPELINING
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-CHUNKING
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250-REQUIRETLS
Fri 2024-09-20 13:56:48.029: 03: [01998028] --> 250 SIZE 51200000
Fri 2024-09-20 13:56:48.057: 02: [01998028] <-- AUTH PLAIN ******
Fri 2024-09-20 13:56:48.057: 01: [01998028] Autentificando user@mydomain.es
Fri 2024-09-20 13:56:48.058: 01: [01998028] Authenticated as user@mydomain.es
Fri 2024-09-20 13:56:48.058: 03: [01998028] --> 235 2.7.0 Authentication successful
Fri 2024-09-20 13:56:48.073: 02: [01998028] <-- MAIL FROM:<user@mydomain.es> BODY=8BITMIME SIZE=5679
Fri 2024-09-20 13:56:48.074: 03: [01998028] --> 250 2.1.0 Sender OK
Fri 2024-09-20 13:56:48.097: 02: [01998028] <-- RCPT TO:<xxxxxxxxxxx@berger-levrault.com>
Fri 2024-09-20 13:56:48.099: 03: [01998028] --> 250 2.1.5 Recipient OK
Fri 2024-09-20 13:56:48.129: 02: [01998028] <-- DATA
Fri 2024-09-20 13:56:48.129: 03: [01998028] --> 354 Enter mail, end with <CRLF>.<CRLF>
Fri 2024-09-20 13:56:48.158: 01: [01998028] Message size: 5679 bytes
Fri 2024-09-20 13:56:48.211: 01: [01998028] Creación del mensaje successful: c:\mdaemon\queues\inbound\md5001001593856.msg
Fri 2024-09-20 13:56:48.211: 03: [01998028] --> 250 2.6.0 Ok, message saved <Message-ID: <68a6816c-f61b-4c5b-a539-ad866551465c@aytocuellar.es>>
Fri 2024-09-20 13:56:53.679: 02: [01998028] <-- QUIT
Fri 2024-09-20 13:56:53.680: 03: [01998028] --> 221 2.0.0 See ya in cyberspace
Fri 2024-09-20 13:56:53.680: 01: [01998028] SMTP session successful (Bytes in/out: 6992/3239)
> Was the message received from an IP address that was excluded from BackScatter?No, the IP 10.104.1.100 and the IP 192.168.23.27 aren't excluded from BackScatter
>Was the MAIL FROM value alredy BATV encoded when MDaemon received the message?I think the MAIL FROM value wasn't encoded according to the log line:
Fri 2024-09-20 13:56:48.073: 02: [01998028] <-- MAIL FROM:<user@mydomain.es> BODY=8BITMIME SIZE=5679Best regards
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Arron Staff
Am I understanding correctly that the IP the message was received from is not in the Exclusion list for BackScatter? If the IP is not in the exclusion list, then MDaemon should have encoded the MAIL FROM value. If you don't want it to be BackScatter encoded, the you'll need to turn off BackScatter or add the IP address to the exclusion list.
You can also exclude an entire domain, if that will work better for you.
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Hello Arron
I've included in exclusion list the subnet (192.168.0.0\16) of the IP of the machine from which I send a new test mail. The MAIL FROM (of the smtp session with the ISP smtp server) is encoded, so the smtp server reject the mail.
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Arron Staff
CIDR notation should be 192.168.0.0/16. Notice the different slash.
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Also I tried to use the slash in both directions with the same result
By the way, in the comments with examples in the file with exclusions of BackScatter, the slash appears with this form: "\", I thought this is an error and because of this, I tried with both form of slash. I suppose this should be fixed.
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Arron Staff
Also I tried to use the slash in both directions with the same result
Sorry, I was wrong about how the exclusion list works. To prevent the MAIL FROM value from being backscatter encoded you'll need to enter the recipient's email address domain. So if you are sending to arron@company.test, then you'd enter company.test.
Are there messages that you need to have BackScatter encoded? If not, the easiest approach might just be to turn off backscatter protection.
Another option, instead of turning it off, would be to send all mail directly, instead of sending it through the smart host.
By the way, in the comments with examples in the file with exclusions of BackScatter, the slash appears with this form: "\", I thought this is an error and because of this, I tried with both form of slash. I suppose this should be fixed.
I believe this is already fixed. If you delete the file and restart MDaemon, the file will be recreated with the most up to date comments.
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Hello Arron
If the value to exclude is the recipient's email address (or theirs domain), it isn't funtional for me because I don't know with which mails (domains) I'll need it.
I've configured Mdaemon to send the mail directly and if Mdaemon can't send it for any reason, then use the smart host to send the mails. So, I don't know previously which domains need exclude.
I'm afraid I must disable BackScatter protection.
Anyway, I think It would be much more logical that the excludes of BackStatter Protection would work as you said on the first time: exclude the name or IP of the SMTP Servers which doesn't support this feature.
Best Regards
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After rename the file "BATVXcpt" and restart Mdaemon, the new file have the same incorrect line:
# Ex: 127.0.0.1 o 192.0.2.0\24 o *.example.com, un registro por línea.
Note: this is spanish version
On other hand, I've disabled Backscatter protection, and now the mail for tests which I've used this previous days, has been correctly sent to smart host
Best Regards
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Arron Staff
Thank you for the feedback.
We'll look into adjusting how the exceptions work for backscatter in a future version.
We found the incorrect string and will fix it for the next version.
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Ok
Thank you very much
Best regards
