My SubNet Can't Connect to DALnet

Without clear reason DALnet (without I know why) whole of my IP on PCM SubNet can't connect to DALnet. The result is I've to up some local virtual IP from LA for SNAT.

ifconfig eth0:1 202.152.23.51 netmask 255.255.255.240 broadcast 202.152.23.63
ifconfig eth0:2 202.152.23.52 netmask 255.255.255.240 broadcast 202.152.23.63
ifconfig eth0:3 202.152.23.53 netmask 255.255.255.240 broadcast 202.152.23.63
ifconfig eth0:4 202.152.23.54 netmask 255.255.255.240 broadcast 202.152.23.63

Then SNAT-ing...

iptables -t nat -A POSTROUTING -s 202.52.207.99/255.255.255.255 -p tcp -d 61.6.39.100/255.255.255.255 -j SNAT -o eth0 --to-source 202.152.23.51
iptables -t nat -A POSTROUTING -s 202.52.207.100/255.255.255.255 -p tcp -d 61.6.39.100/255.255.255.255 -j SNAT -o eth0 --to-source 202.152.23.52
iptables -t nat -A POSTROUTING -s 202.52.207.101/255.255.255.255 -p tcp -d 61.6.39.100/255.255.255.255 -j SNAT -o eth0 --to-source 202.152.23.53
iptables -t nat -A POSTROUTING -s 202.52.207.102/255.255.255.255 -p tcp -d 61.6.39.100/255.255.255.255 -j SNAT -o eth0 --to-source 202.152.23.54

Ok, now all of the PCM IP has been SNAT-ing to LA IP. Hope its not last forever... I'm curently contacting DALnet for explanation.