sendmail 8.14 has a serious memory corruption bug in it

Bill Hacker wbh at
Tue Feb 19 13:59:10 PST 2008

Matthew Dillon wrote:
    Uh, Bill, I think you are misinterpreting the thread.  He's simply saying
    that PacBell won't assign reverse DNS for his IP.  It has nothing to do
    with RFC's, sendmail, or anything else.

I beg to differ ...

Yes - not being willing [1] AND able to *get* a PTR RR is one issue [2].

But criticising an MTA admin (your server...) - especially in this day 
and age - for not accepting traffic for lack of valid DNS (in general) 
and PTR RR in particular, I quote:

>> "If someone rejects mails based on some local rules, then he might
>> not receive a reply..."
. .. and not being inherently aware that this is no mere 'local rule' but 

. .. is head-up-and-locked behaviour from the general public - and badly 
in need of enlightenment in the case of anyone involved in devel of what 
remains the most heavily-used MTA on the planet (sendmail).

Sendmail CAN and generally DOES do the right thing - when configured by 
those 'aware' - and the sendmail docs show the way.

Otherwise, bitching that a(ny) mailadmin should let down essential 
guards is simply no longer an option. Too many WinCrobes, too little 


and this is all old-hat on various MTA mailing lists, deosn't really 
belong here 'atall'.



[1] Lest we forget, it was this very same rejection - from *your* server 
in fact, that caused me a year or three ago to get off my own lazy 
backside, send an e-mail, follow-up by phone...

. . and get a PTR RR into place for *my* MTA in just about five 
wall-clock minutes.

OTOH, we did/do have the appropriate grade of service contract - a full 
rack in a data center with 24x7 admin staff on-site.

[2] Or using the ISP's host when you cannot get what you know you need.

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