Asanka's Notepad

Tag: cisco

  • Setting up NTP, Timezone and DST setting on a Cisco rotuer

    Simply use the following example to setup the router to get date time from a NTP server and show the current time according to the timezone and DST settings.

    The below example configures a NTP server, then sets the time zone for GMT+10 and sets the DST time frames.

    Router(config)#ntp server x.x.x.x
    Router(config)#clock timezone AEST 10 0
    Router(config)#clock summer-time AEDT recurring 1 Sun Oct 2:00 1 Sun Apr 3:00

  • Setting up a Cisco router for auto-provisioning of Cisco handsets

    Here is a sample config to setup auto-provisioning for Cisco handsets. This only covers the part of distributing the config files to the handsets and not the config file creation part.

    This assumes that VLAN100 is the VOICE VLAN and PCs are connecting via the PC port at the back of the phones.

    !
    ip dhcp pool VOICE
    network 192.168.100.0 255.255.255.0
    default-router 192.168.100.1
    dns-server 192.168.100.1
    option 66 ascii "http://auto.provisioning.url/"
    lease infinite
    !
    interface Vlan100
    description VoiceVLAN
    ip address 192.168.100.1 255.255.255.0
    ip nat inside
    ip virtual-reassembly in
    !
    interface FastEthernet3
    description ToVoiceSwitch
    switchport mode trunk
    switchport voice vlan 100
    !

  • Disabling inter-VLAN routing using ACLs

    While working on a customer’s router config he requested the following to be done.

    • 3 LAN subnets
    • IP’s must assigned by DHCP.
    • All 3 subnets must have access to internet.
    • Devices on each LAN should not be able to communicate with each other.

    As the customer had a Cisco 881 the easiest way this could be achieved is with VLANs.  Here’s how I did it.

    inter-vlan

    !
    ip dhcp pool LAN
    network 192.168.1.0 255.255.255.0
    dns-server 220.233.0.3 58.96.1.28 8.8.8.8
    default-router 192.168.1.1
    !
    ip dhcp pool LAN2
    network 192.168.2.0 255.255.255.0
    dns-server 220.233.0.3 58.96.1.28 8.8.8.8
    default-router 192.168.2.1
    !
    ip dhcp pool LAN3
    network 192.168.3.0 255.255.255.0
    dns-server 220.233.0.3 58.96.1.28 8.8.8.8
    default-router 192.168.3.1
    !
    interface FastEthernet0
    no ip address
    !
    interface FastEthernet1
    switchport access vlan 2
    no ip address
    !
    interface FastEthernet2
    switchport access vlan 3
    no ip address
    !
    interface FastEthernet3
    no ip address
    shutdown
    !
    interface FastEthernet4
    ip address 58.96.0.0 255.255.255.254
    ip nat outside
    ip virtual-reassembly in
    rate-limit output 9800000 1250000 2500000 conform-action transmit exceed-action drop
    duplex full
    speed 100
    !
    interface Vlan1
    ip address 192.168.1.1 255.255.255.0
    ip access-group 101 in
    ip nat inside
    ip virtual-reassembly in
    !
    interface Vlan2
    description LAN2
    ip address 192.168.2.1 255.255.255.0
    ip access-group 102 in
    ip nat inside
    ip virtual-reassembly in
    !
    interface Vlan3
    description LAN3
    ip address 192.168.3.1 255.255.255.0
    ip access-group 103 in
    ip nat inside
    ip virtual-reassembly in
    !
    ip nat inside source list 1 interface FastEthernet4 overload
    !
    access-list 1 permit 192.168.0.0 0.0.3.255
    access-list 1 permit any
    access-list 101 deny ip 192.168.1.0 0.0.0.255 192.168.2.0 0.0.0.255
    access-list 101 deny ip 192.168.1.0 0.0.0.255 192.168.3.0 0.0.0.255
    access-list 101 permit ip any any
    access-list 102 deny ip 192.168.2.0 0.0.0.255 192.168.1.0 0.0.0.255
    access-list 102 deny ip 192.168.2.0 0.0.0.255 192.168.3.0 0.0.0.255
    access-list 102 permit ip any any
    access-list 103 deny ip 192.168.3.0 0.0.0.255 192.168.1.0 0.0.0.255
    access-list 103 deny ip 192.168.3.0 0.0.0.255 192.168.2.0 0.0.0.255
    access-list 103 permit ip any any
    !