Maybe Exim should get a feature where you can define "protocol overrides" for domains, like so it ignore specific protocol violations and such. So if you have problem with a slightly misbehaving remote mail server, you can in a acl define how exim should treat its responses (for example, treat it as temporary rejection, permanent rejection, or just ignore it) - at different stages in the connection.
-----Ursprungligt meddelande----- Från: Jeremy Harris via Exim-users <[email protected]> Skickat: den 3 september 2021 00:46 Till: [email protected] Ämne: Re: [exim] exim cant handle 521 response from remote MX On 02/09/2021 20:25, krzf83--- via Exim-users wrote: >>> Large email provider in my country uses 521 response at their MX for >>> some kind of delaying. They don't care that its against rfc1846 >>> >>> rfc1846 says:" A host which sends a 521 greeting message MUST NOT be >>> listed as an MX record for any domain" >>> >>> # nc mx.poczta.onet.pl 25 >>> 220-mx.poczta.onet.pl ESMTP >>> 521 5.7.1 Service unavailable; client [144.76.50.172] blocked using >>> postscreenbl.opbl.onet.pl.local That is not a consistent response. The first line is a 220 (with a flag saying it will be a multi-line response). The second is a 521 (without the flag, hence the last line). All the lines of the response should have the same code (RFC 5321 section 4.2.1 last para: "In a multiline reply, the reply code on each of the lines MUST be the same." ) For what it's worth, testing from here gets a two-line response but with 220 for both. -- Cheers, Jeremy -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
smime.p7s
Description: S/MIME Cryptographic Signature
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