null mx record check #22
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| # value. If it's value is 0 it should return null MX. | ||
| if len(records) > 0: | ||
| for rdata in records: | ||
| if rdata.preference == 0: |
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issue: Don't we need to check for a zero length (i.e. .) record in addition to the zero preference? My reading of Section 3 of the RFC says yes. Particularly combined with the SMTP fallback behavior of, "If an empty list of MXs is returned, the address is treated as if it was associated with an implicit MX RR, with a preference of 0, pointing to that host," and the examples at the end of RFC 974, it seems like zero does not imply by itself that it's a null MX record.
A test of the behavior would be good to show that it works as intended.
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Thank you @michaelherold after reading the RFC I agree with your comments above. Further it is now my understanding that a Null MX record should also only consist of a single MX record with 0 preference and an empty label. I have updated the code accordingly and added some tests to verify that it works as intended. Please review and let me know your thoughts. |
pyisemail/diagnosis/dns_diagnosis.py
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| @@ -21,4 +21,5 @@ class DNSDiagnosis(BaseDiagnosis): | |||
| "Couldn't find an MX record for this domain " "but an A record does exist." | |||
| ), | |||
| "NO_RECORD": "Couldn't find an MX record or A record for this domain.", | |||
| "NULL_RECORD": "Domain does not support email service." | |||
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There's a small issue here that I will fix when rebasing. This needs to match the key above.
michaelherold
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To address issue michaelherold#10 this adds the ability to check for a null MX record, as defined by RFC 7505 section 3. Also added tests to verify that it is working correctly.
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To address issue #10 this adds the ability to check for a null MX record.
It also adds a new error code NULL_MX_RECORD.