RE: [Ext] trolling

[Gary Sparkes via NANOG <nanog () lists nanog org>]

Can confirm on that one, Exchange / Outlook are the ones that play extremely well in this scenario. Microsoft learned 
these lessons very early on.... One hilarious example was internal to them in 1997, for instance (not the same type of 
problem, but still one of many things that they learned well early in exchange's life). 

For all MS's faults, Exchange really is a damn good product at the end of the day if it's set up per documentation (ie: 
not a single server) and you actually use any of its functionality. It's the most set-it-and-forget-it and self-healing 
system outside of normal patching I've ever had to deal with at scale (largest of 70k users, smallest of 100 users). 

-----Original Message-----
From: Ryan Hamel via NANOG <nanog () lists nanog org> 
Sent: Tuesday, November 11, 2025 2:16 AM
To: nanog () lists nanog org
Cc: Ryan Hamel <ryan () rkhtech org>
Subject: Re: [Ext] trolling

Endre,

Exchange only sends one reply to each sender 
(https://learn.microsoft.com/en-us/troubleshoot/exchange/client-connectivity/one-reply-sent-sender), and it's also 
configurable too 
(https://learn.microsoft.com/en-us/troubleshoot/exchange/email-delivery/understand-troubleshoot-oof-replies).

Ryan Hamel

________________________________
From: Endre Szabo via NANOG <nanog () lists nanog org>
Sent: Monday, November 10, 2025 10:50 PM
To: nanog () lists nanog org <nanog () lists nanog org>
Cc: Endre Szabo <endre.szabo@nanog-list-sfegrr.redir.email>
Subject: Re: [Ext] trolling

Caution: This is an external email and may be malicious. Please take care when clicking links or opening attachments.


On Mon, Nov 10, 2025 at 15:14:26+0000, Giorgio Bonfiglio via NANOG wrote:
> Also, speaking about technical limitations - which mailserver in the world does send one auto-reply PER MESSAGE to 
> the same sender? I haven't seen this in ages, most seem to be sending only once or at worst once every day or so.

Oh, I know the answer to this one! It's a niche player in the market, and it's well known for not following standards 
or best practices. Like, they could have ignored messages with List-* headers, for example, right? The server in 
question is called Microsoft Exchange.

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