anyone can help with this thing?
**my problem is :
- router ping client = success
- client ping router = RTO**
I have no firewall setting about blocking icmp, but why this happen?
Too much information, next time just ask “Why?” without everything else…
And don't SCREAM in the title ... please 
Just to be sure, isn’t there a general drop or reject rule (no strings attached)?
You don’t have to specify icmp directly to block it.
Please also check again what is in the input and output chain.
More information usually leads to better and more accurate answers.
Please check the firewall policy, or look at the routing table