Category Archives: IP

Missing Interfaces in

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Have you have ever been in a situation (typically in a virtualised environment) where you have added another network adapter & it didn’t seem to appear in Ubuntu? In the following example, I added a second interface, however it didn’t just simply appear. The following is this issue was resolved.

~$ ifconfig
ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.115.199 netmask 255.255.255.0 broadcast 192.168.115.255
inet6 fe80::250:56ff:fe9c:a2df prefixlen 64 scopeid 0x20<link>
ether 00:50:56:9c:a2:df txqueuelen 1000 (Ethernet)
RX packets 2846 bytes 359600 (359.6 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 159 bytes 18009 (18.0 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 358 bytes 26926 (26.9 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 358 bytes 26926 (26.9 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

As you can see in the ‘ifconfig’ output, there is no additional ethernet interface. So lets use the command ‘ip link’

~$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
link/ether 00:50:56:9c:a2:df brd ff:ff:ff:ff:ff:ff
3: ens192: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 00:50:56:9c:56:c4 brd ff:ff:ff:ff:ff:ff

You can see that there is in fact an additional interface, however it hasn’t been configured yet. So lets use nano to edit the interfaces file and add it.

~$ sudo nano /etc/network/interfaces

 

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto ens160
iface ens160 inet static
address xxx.xxx.xxx.xxx
netmask 255.255.255.0
network xxx.xxx.xxx.xxx
broadcast xxx.xxx.xxx.xxx
gateway xxx.xxx.xxx.xxx
auto ens192
iface ens192 inet dhcp

We add the additional information underlined in this example, exit & save, then we need to restart the network service

~$ sudo systemctl restart networking

Be warned, if you are logged into the server via SSH, your connection will drop, as you’re restarting the whole networking service. Run the ‘ifconfig’ command again to verify that you have your new interface.

~$ ifconfig
ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.115.199 netmask 255.255.255.0 broadcast 192.168.115.255
inet6 fe80::250:56ff:fe9c:a2df prefixlen 64 scopeid 0x20<link>
ether 00:50:56:9c:a2:df txqueuelen 1000 (Ethernet)
RX packets 622 bytes 74509 (74.5 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 79 bytes 10801 (10.8 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

ens192: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::250:56ff:fe9c:56c4 prefixlen 64 scopeid 0x20<link>
ether 00:50:56:9c:56:c4 txqueuelen 1000 (Ethernet)
RX packets 25 bytes 4043 (4.0 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 19 bytes 2897 (2.8 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 367 bytes 27739 (27.7 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 367 bytes 27739 (27.7 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

As we can see by the output, we now have the new interface.

 

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Setting the management interface IP address on Palo Alto Networks Firewalls via CLI

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>configure

# set deviceconfig system ip-address 10.0.0.2 netmask 255.255.255.0 default-gateway 10.0.0.1 dns-setting servers primary 8.8.8.8

# commit

Password Recovery on Cisco 1800 series

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Every now & then I have to reset or reconfigure an older Cisco device that I come across in my day to day. This is just for me personally to remember. If it helps you too, then your welcome! 😉

Please see the regular process to reset the password on 1841 Router below,

  • Use the console to connect to the 1841
  • Use the power switch in order to turn off the router, and then turn the router back on
  • SEND BREAK within 60 seconds of power up in order to put the router into ROMMON
  • Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash

This step bypasses the startup configuration where the passwords are stored

  • Type reset at the rommon 2> reset

The router reboots, but ignores the saved configuration.

  • Type no after each setup question, or press Ctrl-C in order to skip the initial setup procedure.
  • Type enable at the Router> prompt.
  • You are in enable mode and should see the Router# prompt.
  • Type copy startup-config running-config in order to copy the nonvolatile RAM (NVRAM) into memory.

Important:

Do not type copy running-config startup-config or write. These commands erase your startup           configuration.

  • Type configure terminal
  • Type #enable secret <password> in order to change the enable secret password.
  • Type config-register #config-register 0x2102
  • Type write memory or #copy running-config startup-config in order to commit the changes
  • RELOAD

Refer:

http://www.cisco.com/en/US/products/hw/routers/ps221/products_password_recovery09186a0080094773.shtml

Introduction to A/V over ethernet networks

In this string of blog posts i’ll be discussing the latest generations of concept, standards & protocols being deployed by A/V vendors to simplify & lower the costs of infrastructure with the use of standards based (IEEE 802.3) ethernet & IP. I will be writing more specifically about vendors specific protocols, but in doing so, will also aim to educate the community on the basic subjects of ethernet & IP. I’ll be using tools like Wireshark to capture the traffic & dissect the ethernet frames to further learn more about the protocols used.

The starting vendors proprietary protocol will be Audinate’s Dante, at the same time we’ll look at the basics of the OSI model, layer 1 (physical), layer 2 (data link), layer 3 (network), unicast vs multicast, UDP & TCP packets along the way. Hardware will also be discussed as each hardware vendors implementation of these proprietary protocols differs slightly to allow for certain functionality within a closed system.