HI Team, Trying to make this code work; but some how it is entering the if condition mentioned below.sock_buff is still a NULL Pointer.I can see that Function was registered with the Ipv4 Hooks. Any ideas/scenarios where the sock_buff remains as NULL Pointer??? Testing this code by trying to do ssh with this machine. Any Help is really appreciated !! ######### static struct nf_hook_ops netfilter_ops; struct sk_buff *sock_buff; unsigned int main_hook(unsigned int hooknum,struct sk_buff **skb,const struct net_device *in,const struct net_device *out,int (*okfn)(struct sk_buff*)) { sock_buff = *skb; if(!sock_buff){ printk(KERN_ERR "Entered unexpected loop \n"); return NF_ACCEPT; }/* Check for sk_buff NULL */ } int init_module() { netfilter_ops.hook = (nf_hookfn *) main_hook; netfilter_ops.hooknum = NF_INET_PRE_ROUTING; netfilter_ops.pf = PF_INET; netfilter_ops.priority = NF_IP_PRI_FIRST; nf_register_hook(&netfilter_ops); } ###################### -Thnx, VKS