USG2210 firewall uses PPOE dial-up access to the Internet successful, client access to the Internet normally, but some of the web pages can not be opened. For example, 139 mailboxes open the login screen, enter the user name password success, but the page can not display out, it is blank.
1. Through the client PC ping Baidu domain name, be able to resolve, it means DNS has no problem.
2. By modifying the interface of the dial-up port, the problem still exists.
3. In global mode, modify the TCP fragmentation value, and change the fragmentation value into small. For example: firewall tcp-mss 1000. By testing, the problem could be solved.
1. DNS problem.
2. MTU value problem.
3. The TCP fragmentation problem.
If you can access to the Internet by USG but can not open web pages, you should be:
1. Firstly, test DNS whether there is no problem;
2. If the DNS has no problem, testing and observe the device display phenomenon, if all the web pages can not be opened: change export MTU value and test; if it is some of the web pages can not be opened: change the TCP fragmentation value under the global mode and test.