Re: [mailop] suggested max received headers/hop limit

2022-03-15 Thread Bastian Blank via mailop
On Sat, Mar 12, 2022 at 02:31:14AM +0100, Ángel via mailop wrote: > E.g. your email arrives to the on-premises MTA, which not finding a > local user passes it to Office 365 who doesn't have that either so it > is sent again to on-pre But this is a real mail loop. One system needs to be

Re: [mailop] suggested max received headers/hop limit

2022-03-11 Thread John Levine via mailop
According to à ngel via mailop : >On 2022-03-10 at 15:28 -0500, John Levine via mailop wrote: >> If you really want to stop mail loops, use a Delivered-To header like >> qmail, Postfix, and Courier do: >> >> https://datatracker.ietf.org/doc/draft-duklev-deliveredto/ > >You still need to stop at

Re: [mailop] suggested max received headers/hop limit

2022-03-11 Thread Ángel via mailop
On 2022-03-10 at 15:28 -0500, John Levine via mailop wrote: > If you really want to stop mail loops, use a Delivered-To header like > qmail, Postfix, and Courier do: > > https://datatracker.ietf.org/doc/draft-duklev-deliveredto/ You still need to stop at *some* hop-count. This approach stops

Re: [mailop] suggested max received headers/hop limit

2022-03-10 Thread John Levine via mailop
It appears that Sebastian Nielsen via mailop said: >Reason to have a hop limit is to prevent infinite loops where 2 email >addresses or servers point on each other. > >So its not good to set a hop limit too high either, without any compensating >controls, like having a high hop limit, but cease

Re: [mailop] suggested max received headers/hop limit

2022-03-10 Thread Grant Taylor via mailop
On 3/9/22 11:06 PM, Sebastian Nielsen via mailop wrote: Reason to have a hop limit is to prevent infinite loops where 2 email addresses or servers point on each other. I'm quite well aware of that and think that such a protection is a good thing. So its not good to set a hop limit too high

Re: [mailop] suggested max received headers/hop limit

2022-03-10 Thread Brandon Long via mailop
ah, we also used 50 for ARC as a "maximum" hop count: https://datatracker.ietf.org/doc/html/rfc8617#section-4.2.1 Brandon On Wed, Mar 9, 2022 at 5:05 PM Brandon Long wrote: > Ours was set to 50 years ago, and we renamed our internal hops to > X-Received to avoid issues with external receivers

Re: [mailop] suggested max received headers/hop limit

2022-03-09 Thread Sebastian Nielsen via mailop
Reason to have a hop limit is to prevent infinite loops where 2 email addresses or servers point on each other. So its not good to set a hop limit too high either, without any compensating controls, like having a high hop limit, but cease delivery if it for example stumbles upon 2 received

Re: [mailop] suggested max received headers/hop limit

2022-03-09 Thread Grant Taylor via mailop
On 3/9/22 4:56 PM, Kelsey Cummings via mailop wrote: Greetings, we've been seeing some issues in our mail infrastructure with regular users hitting >25 hops on messages and I'm wondering if there's a general consensus that the old default of 25 is too low given modern mail flows. If I can

Re: [mailop] suggested max received headers/hop limit

2022-03-09 Thread Michael via mailop
Remember, those limits were set in a 286/1200 baud world, but a sane limit should still be observed, 30-50 hops is plenty On Wed, 9 Mar 2022 17:05:38 -0800 Brandon Long via mailop wrote: > Ours was set to 50 years ago, and we renamed our internal hops to > X-Received to avoid issues with

Re: [mailop] suggested max received headers/hop limit

2022-03-09 Thread Brandon Long via mailop
Ours was set to 50 years ago, and we renamed our internal hops to X-Received to avoid issues with external receivers with stricter limits. The number of hops for most consumer mail isn't high, but enterprise messages can have some really extended hops if it goes through nested mailing lists and

Re: [mailop] suggested max received headers/hop limit

2022-03-09 Thread Kelsey Cummings via mailop
On 3/9/2022 5:05 PM, Brandon Long wrote: Ours was set to 50 years ago, and we renamed our internal hops to X-Received to avoid issues with external receivers with stricter limits. The number of hops for most consumer mail isn't high, but enterprise messages can have some really extended hops

[mailop] suggested max received headers/hop limit

2022-03-09 Thread Kelsey Cummings via mailop
Greetings, we've been seeing some issues in our mail infrastructure with regular users hitting >25 hops on messages and I'm wondering if there's a general consensus that the old default of 25 is too low given modern mail flows. Have any of you had to increase it? Any one know what major