Using NCLU to Troubleshoot Your Network Configuration
The Network Command Line Utility (NCLU) can quickly return a lot of information about your network configuration.
net show Commands
Running net show and pressing TAB displays all available command line arguments usable by net. The output looks like this:
cumulus@switch:~$ net show <TAB>
bfd : Bidirectional forwarding detection
bgp : Border Gateway Protocol
bridge : a layer2 bridge
clag : Multi-Chassis Link Aggregation
commit : apply the commit buffer to the system
configuration : settings, configuration state, etc
counters : net show counters
debugs : Debugs
dot1x : Configure, Enable, Delete or Show IEEE 802.1X EAPOL
evpn : Ethernet VPN
hostname : local hostname
igmp : Internet Group Management Protocol
interface : An interface, such as swp1, swp2, etc.
ip : Internet Protocol version 4/6
ipv6 : Internet Protocol version 6
lldp : Link Layer Discovery Protocol
mpls : Multiprotocol Label Switching
mroute : Static unicast routes in MRIB for multicast RPF lookup
msdp : Multicast Source Discovery Protocol
ospf : Open Shortest Path First (OSPFv2)
ospf6 : Open Shortest Path First (OSPFv3)
package : A Cumulus Linux package name
pbr : Policy Based Routing
pim : Protocol Independent Multicast
ptp : Precision Time Protocol
rollback : revert to a previous configuration state
route : Static routes
route-map : Route-map
snmp-server : Configure the SNMP server
system : System information
time : Time
version : Version number
vrf : Virtual Routing and Forwarding
vrrp : Virtual Router Redundancy Protocol
Show Interfaces
To show all available interfaces that are physically UP, run net show interface:
cumulus@switch:~$ net show interface
Name Speed MTU Mode Summary
-- ------ ------- ----- ------------- --------------------------------------
UP lo N/A 65536 Loopback IP: 10.0.0.11/32, 127.0.0.1/8, ::1/128
UP eth0 1G 1500 Mgmt IP: 192.168.0.11/24(DHCP)
UP swp1 1G 1500 Access/L2 Untagged: br0
UP swp2 1G 1500 NotConfigured
UP swp51 1G 1500 NotConfigured
UP swp52 1G 1500 NotConfigured
UP blue N/A 65536 NotConfigured
UP br0 N/A 1500 Bridge/L3 IP: 172.16.1.1/24
Untagged Members: swp1
802.1q Tag: Untagged
STP: RootSwitch(32768)
UP red N/A 65536 NotConfigured
To show every interface regardless of state, run net show interface all:
cumulus@leaf01:~$ net show interface all
State Name Spd MTU Mode LLDP Summary
----- ------- --- ----- ------------- ---------------------- -------------------------
UP lo N/A 65536 Loopback IP: 127.0.0.1/8
lo IP: 10.0.0.11/32
lo IP: ::1/128
UP eth0 1G 1500 Mgmt oob-mgmt-switch (swp6) IP: 192.168.0.11/24(DHCP)
UP swp1 1G 1500 Access/L2 server01 (eth1) Master: br0(UP)
ADMDN swp2 N/A 1500 NotConfigured
ADMDN swp45 N/A 1500 NotConfigured
ADMDN swp46 N/A 1500 NotConfigured
ADMDN swp47 N/A 1500 NotConfigured
ADMDN swp48 N/A 1500 NotConfigured
ADMDN swp49 N/A 1500 NotConfigured
ADMDN swp50 N/A 1500 NotConfigured
UP swp51 1G 1500 Default spine01 (swp1)
UP swp52 1G 1500 Default spine02 (swp1)
UP br0 N/A 1500 Bridge/L3 IP: 172.16.1.1/24
ADMDN vagrant N/A 1500 NotConfigured
To get information about the switch itself, run net show system:
cumulus@switch:~$ net show system
Hostname......... celRED
Build............ Cumulus Linux 4.0.0~1555370771.772c26b6
Uptime........... 8 days, 12:24:01.770000
Model............ Cel REDSTONE
CPU.............. x86_64 Intel Atom C2538 2.4 GHz
Memory........... 4GB
Disk............. 14.9GB
ASIC............. Broadcom Trident2 BCM56854
Ports............ 48 x 10G-SFP+ & 6 x 40G-QSFP+
Base MAC Address. a0:00:00:00:00:50
Serial Number.... A1010B2A011212AB000001
network-docopt Package
NCLU uses the python network-docopt package. This is inspired by docopt and enables you to specify partial commands without tab completion or running the complete option. For example, net show int runs the net show interface command and net show sys runs the net show system command.