[exim] Exim 4.63 ACL Error ?

I use the standard Exim supplied with Centos 5.6 (Exim version 4.63 #1
built 10-Dec-2010 16:36:10)

I noticed in Logwatch:-

2011-07-06 07:13:46 H=[210.51.1.248]:53078 I=[xx.xx.xx.xx]:25 rejected
connection in "connect" ACL: host lookup failed (210.51.1.248 does not
match any IP address for mail.sailblog.cn): 1 Time(s)

yet:-
    host 210.51.1.248

reveals:-

248.1.51.210.in-addr.arpa domain name pointer mail.sailblog.cn.
248.1.51.210.in-addr.arpa domain name pointer mail.powermail.com.cn.
248.1.51.210.in-addr.arpa domain name pointer sailblog.cn.
248.1.51.210.in-addr.arpa domain name pointer powermail.com.cn.

The ACL is:-


acl_check_connection:

accept  hosts         = /data/config/exim/mx.hosts.accept.a

accept  verify       = reverse_host_lookup

accept






--
With best regards,

Paul.
England,
EU.