[syslog-ng] a question about dns

I use syslog-ng to receive remote logs. In the conf of syslog-ng I use 'use_dns(yes)' option . My question is : there is a remote host which has one ip 10.23.245.158,and two dns: build-la21.com and lrh- build-la21.com, which dns will syslog-ng choose when receive logs from the remote host?