Well, I'm running postfix with the default header_size_limit of 102,400, so I don't think that's the issue and there are no reject messages in the mail logs to indicate any problem. It seems that the mailing list is not always sending me the emails.
Another mystery from the bowels of technology!
Cheers
Bill 
 
-----Original message-----
> From:Steven J. Yellin <[log in to unmask]>
> Sent: Wednesday 21st June 2017 9:04
> To: Bill Maidment <[log in to unmask]>
> Cc: [log in to unmask]
> Subject: RE: Security ERRATA Important: kernel on SL6.x i386/x86_64
> 
>      Last November I was "automatically removed from the 
> SCIENTIFIC-LINUX-USERS list (Mailing list for Scientific Linux users 
> worldwide)  as a result of repeated delivery error reports from your mail 
> system."  So one possibility is that your mail system is occasionally 
> failing to deliver mail to you from this list, but you haven't yet been 
> removed.  In my case, the reason was that the listserver sometimes sends 
> email with a header longer than 32768 bytes, which the SLAC mail system 
> couldn't handle.  FermiLab said such long headers are becoming necessary 
> because "cloud systems that everyone has and will be moving to, add 
> additional diagnostic info in the headers so if people report any errors, 
> they can more easily be diagnosed."  The solution was to convince the 
> managers of SLAC's mail system to increase their incoming header size 
> parameter.
> 
> Steven Yellin
> 
> On Wed, 21 Jun 2017, Bill Maidment wrote:
> 
> > Hi. Is there something wrong with this mailing list? I received this 
> > response, but I never received the original message. This is not the 
> > first time I have noticed this.
> 
> > Cheers
> > Bill
> >
> >
> > -----Original message-----
> >> From:Stephan Wiesand <[log in to unmask]>
> >> Sent: Wednesday 21st June 2017 2:58
> >> To: [log in to unmask]
> >> Subject: Re: Security ERRATA Important: kernel on SL6.x i386/x86_64
> >>
> >> Kudos to the SL team at FNAL for once again getting the updates for a really nasty issue out incredibly quickly. Impressive.
> >>
> >> --
> >> Stephan Wiesand
> >> DESY -DV-
> >> Platanenenallee 6
> >> 15738 Zeuthen, Germany
> >>
> >>
> >
> 
>