Both UDP and TCP does not include source address, but how does it say UDP IP spoofing is easier than TCP? For example, the following webpage also says about UDP vulnerability.
"Unlike TCP, UDP does not have a mechanism for verifying a packet source, which makes it very vulnerable to source-packet spoofing and inception attacks." http://www.onlamp.com/pub/a/onlamp/2004/10/14/dnssec.html
Please help me to understand.