Spamcop can not send me mail

[mrwebman]

I'm getting this notice when I login to Spamcop web interface:

Bounce error
Your email address, my email address has returned a bounce:
Subject: Delivery Status Notification (Failure)
Reason: 5.4.7 - Delivery expired (message too old) 550-'Reverse DNS verification fa=

How do I fix a reverse DNS issue like this?  The mail server's DNS records look fine to me but I must be missing something.

Thanks

[petzl]

2 hours ago, mrwebman said:

I'm getting this notice when I login to Spamcop web interface:

Bounce error
Your email address, my email address has returned a bounce:
Subject: Delivery Status Notification (Failure)
Reason: 5.4.7 - Delivery expired (message too old) 550-'Reverse DNS verification fa=

How do I fix a reverse DNS issue like this?  The mail server's DNS records look fine to me but I must be missing something.

Thanks

Your ISP can do this not you.

[Lking]

The is a possibility that there was a temporary issue with the DNS server, or your server, that caused the timeout/ bounce. If you don't see an issue, I would suggest go back to your SpamCop login and clear the bounce flag.

As long as the flag is set SpamCop will not send you an emails. (As I remember if SC gets 3 (or 6?) bounces SC will set the bounce flag in your account. If the flag gets set again, have a hart to hart with your ISP to fix the real problem.

[WelshProgammer]

I tried configuring a mailhost today and it fails with:

450 4.7.25 Client host rejected: cannot find your hostname, [184.94.240.100]

Postfix when configured with reject_unknown_client_hostname is rejecting the mail because the sender has invalid DNS records:

Quote

reject_unknown_client_hostname (with Postfix < 2.3: reject_unknown_client)

Reject the request when 1) the client IP address->name mapping fails, or 2) the name->address mapping fails, or 3) the name->address mapping does not match the client IP address.
This is a stronger restriction than the reject_unknown_reverse_client_hostname feature, which triggers only under condition 1) above.
The unknown_client_reject_code parameter specifies the response code for rejected requests (default: 450). The reply is always 450 in case the address->name or name->address lookup failed due to a temporary problem.

Postfix logs:

Apr  6 11:44:26 mail postfix/postscreen[1602]: CONNECT from [184.94.240.100]:32832 to [xxxx]:25
Apr  6 11:44:26 mail postfix/postscreen[1602]: PASS OLD [184.94.240.100]:32832
Apr  6 11:44:27 mail postfix/smtpd[33315]: warning: hostname vmx.spamcop.net does not resolve to address 184.94.240.100
Apr  6 11:44:27 mail postfix/smtpd[33315]: connect from unknown[184.94.240.100]
Apr  6 11:44:28 mail postfix/smtpd[33315]: NOQUEUE: reject: RCPT from unknown[184.94.240.100]: 450 4.7.25 Client host rejected: cannot find your hostname, [184.94.240.100]; from=<service@admin.spamcop.net> to=<xxxx> proto=SMTP helo=<prod-sc-www02.spamcop.net>
Apr  6 11:44:28 mail postfix/smtpd[33315]: lost connection after RCPT from unknown[184.94.240.100]
Apr  6 11:44:28 mail postfix/smtpd[33315]: disconnect from unknown[184.94.240.100] helo=1 mail=1 rcpt=0/1 commands=2/3

Is it possible for the SC admins to correctly setup DNS or hostname so that the name is resolved properly?

Currently I get:

nslookup 184.94.240.100
100.240.94.184.in-addr.arpa     name = vmx.spamcop.net.

# dig vmx.spamcop.net mx
;; QUESTION SECTION:
;vmx.spamcop.net.               IN      MX

;; ANSWER SECTION:
NO ANSWER

;; AUTHORITY SECTION:
spamcop.net.            59      IN      SOA     ns1-93.akam.net. hostmaster.akamai.com. 2023032702 300 300 300 300

# dig vmx.spamcop.net a
;; QUESTION SECTION:
;vmx.spamcop.net.               IN      A

;; ANSWER SECTION:
vmx.spamcop.net.        69      IN      A       184.94.240.112

Thanks!

Edited April 6, 2023 by WelshProgammer

[gnarlymarley]

Mine emails seem to be coming from esa1.spamcop.iphmx.com. 68.232.142.20. I see they got the SPF updated.


;; QUESTION SECTION:
;admin.spamcop.net. IN ANY

;; ANSWER SECTION:
admin.spamcop.net. 60 IN A 184.94.240.100
admin.spamcop.net. 60 IN A 216.127.43.88
admin.spamcop.net. 300 IN TXT "v=spf1 ip4:184.94.240.100 ip4:184.94.240.112 ip4:216.127.43.94 ip4:68.232.143.151 ip4:68.232.142.20 ip4:204.15.80.0/22 ip4:216.154.195.32/27 ?all"
admin.spamcop.net. 300 IN MX 10 vmx.spamcop.net.