Re: SPF and SERVFAIL

>I see your record as "v=spf1 ip4:202.168.6.0/24 mx ptr ~all".  It's probably 
>the ptr mechanism that is the source of your problem.  rDNS lookups can be 
>quite problematic and it's possible to construct any SPF record you need 
>without resort to it.  We've marked the ptr mechanism as "deprecated" and 
>recommended people not use it in the RFC 4408bis draft we have in progress.

equally mx is a pretty useless addition to spf as its 1+number of mxs in cost in your case 1 mx so cost=2
using a:bareed.racingvictoria.net.au on the other hand costs 1 dns lookup (and one less chance of fail)

and as this server has 2 ips (and is in the same domain thus any change in its ip you already controll)
replacing it with
 ip4:203.58.18.232 ip4:202.168.6.132 0 cost and 0 chance of servfail
and as one of these ips is in your class c changing your spf from
"v=spf1 ip4:202.168.6.0/24 cost 0
mx cost 2
ptr cost 2(minimum)
~all"

to "v=spf1 ip4:202.168.6.0/24 ip4:203.58.18.232 ~all" cost 0 chance of servfail 0
with no actual change in function