2N OfficeRoute - User manual, 1493 v1.9.0 - Manual (Page 40)

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2N TELEKOMUNIKACE a.s., www.2n.cz
®
DNS Proxy
Used for caching DNS records in case 2N OfficeRoute/2N VoiceBlue Enterprise
® ®
works as a UMTS/GPRS router. The DSN proxy can receive DNS queries from the local
network and forward them to an Internet Domain Name Server. If the DNS Proxy is
disabled, the gateway forwards all requests to the servers assigned by the UMTS (2N
®
) or GPRS ( ) provider. OfficeRoute 2N VoiceBlue Enterprise
®
The gateway can use the DNSs from the or you can forward the Network settings
DNS queries to specified servers.
Figure 3.18: DNS Proxy Configuration
VRRP
The Virtual Router Redundancy Protocol is an Internet protocol, which provides a
possibility to have one or more backup routers when using a statically configured
router on a local area network (LAN). The most common arrangement is to specify one
router to serve as the router for forwarding packets from a group of hosts on a LAN. If
the router fails, however, there is no way to use another router as a backup.
Using VRRP, a virtual IP address can be specified manually or with the Dynamic Host
Configuration Protocol (DHCP) by default. A virtual IP address is shared by the routers,
with one designated as the master and the others as backups. In case the master fails,
the virtual IP address is mapped to the backup router IP address (this backup thus
becomes the master router). If the backup router becomes master, the default
gateway to the PSTN is set automatically. If this new master becomes a backup router
again, the default gateway to LAN (Ethernet interface) is recovered.