Some analysis of Craig's list of just under 6,000 failures
1920 records bad argument to a:
1146 records unrecognized mechanism
1091 records Missing SPF record at
864 records bad argument to ip4:
394 records unable to parse ip4:
291 records no argument given to ip4
171 records loop encountered
93 records include mechanism not given an argument
1 records query caused more than 10 lookups
bad arguments at a: are predominately ip addresses
unrecognized mechanisms are a mix of typos and other mistakes
missing records are from includes
bad argument to ip4: is a mix of typos and other IP address mistakes
unable to parse ip4: is a mix of people who put lots of IP addresses in a string, others
where it's the last modifier and they miss the space before -all, and other typos.
loop encountered is because of includes
So it would not be unreasonable to say that
bad a: arguments cause 32% of the failures -
bad ip4: causes about 26% -
bad includes cause about 23% -
bad mechanisms cause about 19% -
the rest is apparently insignificant
All figures approximate only.
Slainte
JohnP