ZyXEL Communications ZyXEL ZyWALL IDP 10 - Manual (Page 30)

ZyWALL IDP 10 User’s Guide
3-2 General Settings
Table 3-1 General: Device
LABEL DESCRIPTION
System Name Enter a descriptive name of up to 128 single-Byte or double-Byte characters for
identification purposes.
Administrator
Inactivity Timer Type how many minutes a management session (either via the web configurator or SSH)
can be left idle before the session times out. After it times out you have to log in with
your password again. Very long idle timeouts may have security risks. A value of "0"
means a management session never times out, no matter how long it has been left idle
(not recommended).
Device Setup
IP Address Type the IP address of your ZyWALL. If you change the ZyWALL IP address, you will
need to access it again using the new IP address.
Subnet Mask Type the IP subnet mask of your ZyWALL.
Gateway Type the IP address of the gateway. The gateway and DNS entries relate to the e-mail,
syslog and SNMP functions of the ZyWALL.
DNS Server The DNS server maps a domain name to its corresponding IP address and vice versa. If
you configure a DNS server, you can enter an IP address or domain name for e-mail,
syslog, etc. servers.
Apply Click this button to save your changes back to the ZyWALL.
Reset Click this button to begin configuring this screen afresh.
3.2 Introduction to VLANs
A VLAN (Virtual Local Area Network) allows a physical network to be partitioned into multiple
logical networks. Devices on a logical network belong to one group. A device can belong to more than
one group. With VLAN, a device cannot directly talk to or hear from devices that are not in the same
group(s); the traffic must first go through a router.
VLAN increases network performance by limiting broadcasts to a smaller and more manageable
logical broadcast domain.
3.2.1 Tagged VLANs (IEEE 802.1Q)
This section gives some technical background information on tagged VLANs. Skip to section 3.3 to
see how to configure VLAN tagging on the ZyWALL. When a device receives a frame from a
workstation, the VLAN from whence it came must be known so the device may respond, if necessary,
to the source of the frame. This is accomplished by tagging.
IEEE 802.1Q tagged VLAN uses an explicit tag (VLAN ID) in the MAC header to identify the VLAN
membership of a frame across devices - tagged VLANs are not confined to the device on which they
were created.
The VLAN ID associates a frame with a specific VLAN and provides the information that switches
need to process the frame across the network. A tagged frame is four bytes longer than an untagged
frame and contains two bytes of TPID (Tag Protocol Identifier, residing within the type/length field of
the Ethernet frame) and two bytes of TCI (Tag Control Information, a tagged header starts after the
source address field of the Ethernet frame).