While making the Internet totally trustworthy is intractable, making as trustworthy as possible is a crucial problem. Within this landscape, authentication of the IP source address remains one important topic in need of further study. However, most source address validation methods are difficult to implement in practice because of deployment difficulties. This research designs an efficient inter-domain distributed source address validation solution (CatchIt). By employing a novel routing choice notification scheme, CatchIt makes the deployed ASes intelligent by allowing them cooperate to acquire the valid incoming path information of packets. With such knowledge, the deployed ASes can accurately authenticate the source address without the need for any modifications to the de facto routing protocol and packet structure. Moreover, CatchIt helps the deployed ASes proactively and quickly filter spoofed packets before they imperil the network. CatchIt also avoids any false positive, even under partial deployment. Our evaluation also shows that CatchIt is effective and accurate when catching spoofed packets while incurring a low overhead; CatchIt maintains an early deploy and rapidly benefit incremental deployment incentive mechanism.