ZyXEL ISG50-PSTN User Guide - Page 678
Service Access Limitations, System Timeout
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Chapter 52 System Table 273 Configuration > System > DNS > Service Control Rule Add (continued) LABEL Zone DESCRIPTION Select ALL to allow or prevent DNS queries through any zones. Action Select a predefined zone on which a DNS query to the ISG50 is allowed or denied. Select Accept to have the ISG50 allow the DNS queries from the specified computer. OK Cancel Select Deny to have the ISG50 reject the DNS queries from the specified computer. Click OK to save your customized settings and exit this screen. Click Cancel to exit this screen without saving 52.7 WWW Overview The following figure shows secure and insecure management of the ISG50 coming in from the WAN. HTTPS and SSH access are secure. HTTP and Telnet access are not secure. • See Section 6.8.1 on page 104 for related information on these screens. Note: To allow the ISG50 to be accessed from a specified computer using a service, make sure you do not have a service control rule or to-ISG50 firewall rule to block that traffic. • See To-Device Rules on page 354 for more on To-ISG50 firewall rules. • See Section 7.8 on page 123 for an example of configuring service control to block administrator HTTPS access from all zones except the LAN. To stop a service from accessing the ISG50, clear Enable in the corresponding service screen. 52.7.1 Service Access Limitations A service cannot be used to access the ISG50 when: 1 You have disabled that service in the corresponding screen. 2 The allowed IP address (address object) in the Service Control table does not match the client IP address (the ISG50 disallows the session). 3 The IP address (address object) in the Service Control table is not in the allowed zone or the action is set to Deny. 4 There is a firewall rule that blocks it. 52.7.2 System Timeout There is a lease timeout for administrators. The ISG50 automatically logs you out if the management session remains idle for longer than this timeout period. The management session does not time out when a statistics screen is polling. 678 ISG50 User's Guide
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