路由器多运营商接入，出接口某个公网地址不通

路由器由联通双链路，电信双链路接入，4个出接口全部为固定ip，由于运营商给的地址较多，所有在每个出接口下配有多个sub地址，然后四条缺省路由下一跳指到每条线路的网关地址，电信线路缺省路由优先级分别为60、61，联通线路缺省路由优先级为62、63；现在出现的情况是通过公网能ping通电信所有的出接口地址，联通1的出接口地址也能全部ping通，联通2出接口下的58.251.137.242无法ping通，但这个接口下其他的sub地址却可以ping通

4个出接口配置如下

联通1

 interface GigabitEthernet1/5/6/0 

 port link-mode route description connect LianTong-01

  ip address 58.251.137.250 255.255.255.248 

 ip address 58.251.137.251 255.255.255.248 sub

 ip address 58.251.137.252 255.255.255.248 sub

 ip address 58.251.137.253 255.255.255.248 sub 

 ip last-hop hold

 nat outbound

联通2

 interface GigabitEthernet2/5/6/0 

 port link-mode route description connect LianTong-02

 ip address 58.251.137.242 255.255.255.248

 ip address 58.251.137.243 255.255.255.248 sub 

 ip address 58.251.137.244 255.255.255.248 sub 

 ip address 58.251.137.245 255.255.255.248 sub

 ip last-hop hold 

 nat outbound

电信1

interface GigabitEthernet1/5/6/1 

 port link-mode route description to-DianXin-01

 ip address 113.106.79.2 255.255.255.240

 ip address 113.106.79.3 255.255.255.240 sub

 ip address 113.106.79.4 255.255.255.240 sub

 ip address 113.106.79.5 255.255.255.240 sub

 ip address 113.106.79.6 255.255.255.240 sub

 ip address 113.106.79.7 255.255.255.240 sub 

 ip address 113.106.79.8 255.255.255.240 sub 

 ip address 113.106.79.9 255.255.255.240 sub

 ip address 113.106.79.10 255.255.255.240 sub

 ip address 113.106.79.11 255.255.255.240 sub

 ip address 113.106.79.12 255.255.255.240 sub

 ip address 113.106.79.13 255.255.255.240 sub

 ip address 113.106.79.14 255.255.255.240 sub

 ip last-hop hold

电信2

 interface GigabitEthernet2/5/6/1 

 port link-mode route description to-dianxin-02

 ip address 61.144.253.18 255.255.255.240 

 ip address 61.144.253.19 255.255.255.240 sub

 ip address 61.144.253.20 255.255.255.240 sub 

 ip address 61.144.253.21 255.255.255.240 sub 

 ip address 61.144.253.22 255.255.255.240 sub

 ip address 61.144.253.23 255.255.255.240 sub

 ip address 61.144.253.24 255.255.255.240 sub

 ip address 61.144.253.25 255.255.255.240 sub

 ip address 61.144.253.26 255.255.255.240 sub 

 ip address 61.144.253.27 255.255.255.240 sub 

 ip address 61.144.253.28 255.255.255.240 sub 

 ip address 61.144.253.29 255.255.255.240 sub 

 ip address 61.144.253.30 255.255.255.240 sub

 ip last-hop hold

缺省路由

  ip route-static 0.0.0.0 0 61.144.253.17

 ip route-static 0.0.0.0 0  113.106.79.1   preference 61

 ip route-static 0.0.0.0 0 58.251.137.249  preference 62

 ip route-static 0.0.0.0 0 58.251.137.241  preference 63