Handling Process
1 When visit the www.sina.com, check the session table, found out a lot of http request, no DNS sessions.
2 In the ACL of the package filtering between regions, the policy permit only the WWW, reject all of the other requests.
acl number 3005
rule 10 permit tcp source 192.168.0.0 0.0.0.255 destination-port eq www
rule 500 deny ip source 192.168.0.0 0.0.0.255
3 Chang the ACL rule, permit the DNS visit.
Root Cause
In the ACL of the package filtering between regions, the policy permit only the WWW, not the DNS, result in the unable to resolve the webpage.Solution
Suggestions
In the package filtering, DNS is of the uncared-for, so we should consider some crytic visit conditions.