[Mailman-Users] cause of bounces

[Dimitri Maziuk]

On 10/18/2017 01:30 PM, Grant Taylor via Mailman-Users wrote:

> The (decimal) number 17 can be encoded multiple ways:
> 
> 10001 = binary      base  2
>    25 = hex         base  6
>    21 = octal       base  8
>    17 = decimal     base 10
>    11 = hexadecimal base 16
> 
> All five encoded numbers represent the same value (decimal) 17.

17 == 0x11. "17" != "0x11". Which was precisely the point: if your MTA,
say, does unicodedata.normalize( 'NFKD' ... ), and turns u-umlaut into a
regular "u", you may consider it benign. Many won't. Most importantly,
crypto signature will change, and DKIM check will fail.

Benign is in the eye of the beholder. We're inserting this stuff into a
database where a search for "Wutrich" will find neither "Wütrich" nor
"W\u0308trich" so I wouldn't consider it benign at all.

-- 
Dimitri Maziuk
Programmer/sysadmin
BioMagResBank, UW-Madison -- http://www.bmrb.wisc.edu

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