On Fri, Jul 11, 2008, Michael Jennings wrote:

> On Friday, 11 July 2008, at 18:29:06 (+0200),
> Ralf S. Engelschall wrote:
>
> > Ah, I see: your are sending from a host which has no PTR record in
> > the DNS.
>
> No, he's sending from a host with intermittent DNS failures:
>
> mej@quasar ~ >> host 17.148.16.88
> 88.16.148.17.in-addr.arpa domain name pointer asmtpout013.mac.com.
>
> So clearly there *is* a PTR record...rpm5.org just didn't find it at
> the time.  Are you not using a local caching DNS server?

Yes, the box is running a local BIND as a caching DNS server.
And, yes, _currently_ the box can resolve the IP:

| root@rpm5:/root
| # nslookup  17.148.16.88
| Server:         10.10.0.1
| Address:        10.10.0.1#53
|
| Non-authoritative answer:
| 88.16.148.17.in-addr.arpa       name = asmtpout013.mac.com.
| [...]

Hmmmm... as a workaround I've made a local /etc/hosts entry for this IP.
Let's see whether it helps Jeff to get his mails through...

                                       Ralf S. Engelschall
                                       rse@engelschall.com
                                       www.engelschall.com