ldirectord 不能检测到21 110 端口的服务（未解决）

ldirectord 不能检测到21 110 端口的服务
其他的80 25 倒是可以检测到
然后，确认了21 110在app上面是开的
然后，手工用ipvsadm 进行添加，发现是可以的导流到21 110 端口
用ldirectord 就是不行！

ldirectord.cf内容：
# Global Directives
checktimeout=3
checkinterval=1
autoreload=yes
logfile="/var/log/ldirectord.log"
quiescent=yes

# -------------------------------------------------------
# HTTP virtual service
virtual=192.168.3.200:80
real=192.168.3.50:80 gate weight 1
real=192.168.3.60:80 gate weight 1
service=http
scheduler=wlc
protocol=tcp
checktype=negotiate
persistent=600
checkport=80

# -------------------------------------------------------
# FTP virtual service
virtual=192.168.3.200:21
real=192.168.3.50:21 gate weight 1
service=ftp
checkport=21
scheduler=wlc
persistent=600
protocol=tcp
checktype=negotiate

# -------------------------------------------------------
# SMTP virtual service
virtual=192.168.3.200:25
real=192.168.3.50:25 gate weight 1
service=smtp
scheduler=wlc
protocol=tcp
persistent=600
checktype=negotiate
checkport=25

# -------------------------------------------------------
# POP virtual service
virtual=192.168.3.200:110
real=192.168.3.50:110 gate weight 1
service=pop
scheduler=wlc
persistent=600
protocol=tcp
checktype=negotiate
checkport=110