Qtech QSW-2900-24T4-AC [32/209] Login access list web snmp telnet ip address wildcard

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reply from 192.168.0.100: bytes=32 time<10ms TTL=127

----192.168.0.100 PING Statistics----

5 packets transmitted, 5 packets received, 0% packet loss

round-trip (ms) min/avg/max = 0/0/0

2.4.4 Loopback test command

In global configuration mode, loopback command is used to test exterior of all interfaces; in interface

configuration mode, loopback command is used to test whether the interface is normal, and it can be divided into

interior and exterior. When exterior testing, exterior wire must be inserted (receiving and sending lines of RJ 45

connected directly). Use 4 diferent wires when the speed is less than 100M.

Using loopback command to do the loopback test, interface cannot transmit data packet correctly, and it will

be automatically ended after a certain time. If shutdown command is executed, loopback test fails; when loopback

test is executing, speed, duplex, mdi, vct and shutdown operations are forbidden. After exterior test, pull out the

exterior wire to avoid abnormal communication.

Loopback on all interfaces:

loopback { internal | external }

Loopback on specified interface:

loopback { external | internal }

External means external loopback and internal means internal loopback

For example:

! Loopback on interface Ethernet 0/1

QTECH(config-if-ethernet-0/1)#loopback external

! Loopback on all interfaces

QTECH(config)#loopback internal

2.4.5 Administration IP address restriction

Managed ip address restriction can restrict host IP address or some network interface of switch by restricting

web, telnet and snmp agent, but other IP address without configuration cannot manage switch. By default, three

server possess an address interface of 0.0.0.0, so users of any IP address can manage switch. Different IP address and

mask mean different information. The mask in reverse which is 0.0.0.0 means host address, or it means network

interface. 255.255.255.255 means all hosts. When enabling a configuration, an item of 0.0.0.0 must be deleted. When

receiving a packet, judge the IP address whether it is in the range of managed IP address. If it does not belong to it,

drop the packet and shutdown telnet connection.

Web means accessing IP address restriction of web server; snmp means accessing IP address restriction of

snmp agent; telnet means accessing IP address restriction of telnet; ipaddress means IP address; wildcard means

mask wildcard which is in the form of mask in reverse. 0 means mask this bit, and 1 meams does not mask this bit.