The Model 5400 Series Symantec Gateway Security 2.0 has released hotfixes that address the denial of service attack issue reported against isakmpd.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/34156/entrust-sgs20-readme.txt
Source: https://packetstormsecurity.com/files/34156/entrust-sgs20-readme.txt.html