Networking :: Virtual IP Responds To ArpPing But Not Ping

Operating system: Debian Lenny 5.08 (2.6.26-2-amd64 #1 SMP Tue Jan 25 05:59:43 UTC 2011 x86_64 GNU/Linux).

I have a network iface eth0 with 2 virtual IP addresses (117.20.2.111 117.20.2.112). The virtual IP addresses I have setup by simply running:

Code:
ifconfig eth0:1 117.20.2.111 up

This has worked fine for 2 virtual IP's but the third one (117.20.2.133) will not respond to ping's though it does respond to arpping's. There are no firewall iptable rules:

Code:
iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination

Output of route -n:
Code:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
117.20.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
117.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth0
0.0.0.0 117.20.2.1 0.0.0.0 UG 0 0 0 eth0

Output of ip rou ls:
Code:
117.20.2.0/24 dev eth0 proto kernel scope link src 117.20.2.110
117.0.0.0/8 dev eth0 proto kernel scope link src 117.20.2.111
default via 117.20.2.1 dev eth0