Re: [mailop] IPv6 reverse DNS from office365
$dig +short mail-lo2gbr01lp20200.outbound.protection.outlook.com ::1 dig +short mail-lo2gbr01lp20200.outbound.protection.outlook.com 2a01:111:f400:7e15::200 I spoke with a network engineer at MSFT and this is fixed now. -David ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] IPv6 reverse DNS from office365
On Thu, Feb 10, 2022, Bill Cole via mailop wrote: > Yes, Microsoft has a chronic endemic problem of broken reverse DNS, > in both IPv4 and IPv6. It cannot be relied upon. So does Google reject mail from those misconfigured Microsoft systems? -- Please don't Cc: me, use only the list for replies. ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] IPv6 reverse DNS from office365
On 2022-02-10 at 05:16:47 UTC-0500 (Thu, 10 Feb 2022 10:16:47 +) Tim Bray via mailop is rumored to have said: > When we receive from 2a01:111:f400:7e15::200 this reverse lookups to > mail-lo2gbr01lp20200.outbound.protection.outlook.com. > > but when you forward check > mail-lo2gbr01lp20200.outbound.protection.outlook.com. it resolves to ::1 Yes, Microsoft has a chronic endemic problem of broken reverse DNS, in both IPv4 and IPv6. It cannot be relied upon. MOST of their active sources are fine: HELO and PTR agree and their names resolve back to their client IPs. Some are just wrong for no obvious reason and with no obvious pattern. -- Bill Cole b...@scconsult.com or billc...@apache.org (AKA @grumpybozo and many *@billmail.scconsult.com addresses) Not Currently Available For Hire ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
Re: [mailop] IPv6 reverse DNS from office365
On Thu, 10 Feb 2022, Tim Bray via mailop wrote: Hi, Is anybody else having trouble relaying email out of office365. I think they have broken their reverse DNS. Our method to trust *.outbound.protection.outlook.com 2022-02-10 09:51:46 H=(GBR01-LO2-obe.outbound.protection.outlook.com) [2a01:111:f400:7e15::200] When we receive from 2a01:111:f400:7e15::200 this reverse lookups to mail-lo2gbr01lp20200.outbound.protection.outlook.com. but when you forward check mail-lo2gbr01lp20200.outbound.protection.outlook.com. it resolves to ::1 Which is when I think exim goes `I'll ignore than DNS record` I'm just interested if anybody has the same problem. A new problem that started sometime since 2022-02-09 20:39:38 UTC. (our users don't send much email over night in UK time. I can confirm that there's something weird with their DNS with IPv6. $ dig +short GBR01-LO2-obe.outbound.protection.outlook.com 2a01:111:f400:7e15::200 $ dig +short -x 2a01:111:f400:7e15::200 mail-lo2gbr01lp20200.outbound.protection.outlook.com. $dig +short mail-lo2gbr01lp20200.outbound.protection.outlook.com ::1 Using A (IPv4) records there's no issue. Cheers.___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
[mailop] IPv6 reverse DNS from office365
Hi, Is anybody else having trouble relaying email out of office365. I think they have broken their reverse DNS. Our method to trust *.outbound.protection.outlook.com 2022-02-10 09:51:46 H=(GBR01-LO2-obe.outbound.protection.outlook.com) [2a01:111:f400:7e15::200] When we receive from 2a01:111:f400:7e15::200 this reverse lookups to mail-lo2gbr01lp20200.outbound.protection.outlook.com. but when you forward check mail-lo2gbr01lp20200.outbound.protection.outlook.com. it resolves to ::1 Which is when I think exim goes `I'll ignore than DNS record` I'm just interested if anybody has the same problem. A new problem that started sometime since 2022-02-09 20:39:38 UTC. (our users don't send much email over night in UK time. Tim Bray ___ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
