### VLAN Troubleshooting
! How we can create Vlans
#Use coma
SW1(config)#vlan 111,112,113
SW1(config-vlan)#exit
SW1(config)#do show vlan brief | in VLAN011
111 VLAN0111 active
112 VLAN0112 active
113 VLAN0113 active
#Use range
SW1(config)#vlan 111-117,119
SW1(config-vlan)#exit
SW1(config)#do show vlan brief | in VLAN011
111 VLAN0111 active
112 VLAN0112 active
113 VLAN0113 active
114 VLAN0114 active
115 VLAN0115 active
116 VLAN0116 active
117 VLAN0117 active
119 VLAN0119 active
# T-Shoot VLAN Config
! We have 2 pc connected into (VLAN 100) Fa0/3 and Fa0/4 in same subnet but Ping doesn´t work.
SW1#show vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/5, Fa0/6, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/11, Fa0/12, Fa0/13, Fa0/14, Fa0/15
Fa0/16, Fa0/17, Fa0/18, Fa0/19, Fa0/20, Fa0/21
Fa0/22, Gi0/1, Gi0/2
100 VLAN0100 act/unsup Fa0/4
<Omitted Lines>
! Port Fa0/3 is missing
! Could fa0/3 be a trunk ?
SW1#show interfaces trunk
Port Mode Encapsulation Status Native vlan
Fa0/23 on 802.1q trunking 1
Fa0/24 on 802.1q trunking 1
<Omitted Lines>
SW1#show interfaces fa0/3 trunk
Port Mode Encapsulation Status Native vlan
Fa0/3 off negotiate other 1
<Omitted Lines>
! No Trunks. Lets look at fa0/3
SW1#show interfaces fastEthernet 0/3
FastEthernet0/3 is up, line protocol is down (monitoring)
Hardware is Fast Ethernet, address is 0017.956e.fa03 (bia 0017.956e.fa03)
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Auto-duplex, Auto-speed, media type is 10/100BaseTX
<Omitted Lines>
! It is a monitoring port.
! Monitoring means that this port is configured as destination port for SPAN.
SW1#show monitor
Session 1
---------
Type : Local Session
Source Ports :
Both : Fa0/4
Destination Ports : Fa0/3
Encapsulation : Native
Ingress : Disabled
! Disable the monitor configuration
SW1(config)#no monitor ses 1
! Now lets take a look again
SW1#show interfaces status | in Fa0/3
Port Name Status Vlan Duplex Speed Type
Fa0/3 Connected 100 auto auto 10/100BaseTX
! But Ping not still works!
SW1#show vlan id 100
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
100 VLAN0100 act/unsup Fa0/3, Fa0/4, Fa0/23, Fa0/24
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
100 fdnet 100100 1500 - - - - - 0 0
<Omitted Lines>
! Now we can see that Status is "unsupported" because Media type says "fdnet".
! We need to change media type for vlan 100
SW1(config)#vlan 100
SW1(config-vlan)#media ?
ethernet VLAN type Ethernet
fd-net VLAN type FDDI Net
fddi VLAN type FDDI
trbrf VLAN type TRBRF
trcrf VLAN type TRCRF
SW1(config-vlan)#media ethernet
SW1(config-vlan)#end
SW1#show vlan id 100
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
100 VLAN0100 act/lshut Fa0/3, Fa0/4, Fa0/23, Fa0/24
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
100 enet 100100 1500 - - - - - 0 0
! But Ping don´t works yet.
! We can see that the status is "lshut" it´s don´t loog good.
! This status means that someone has shutdown vlan 100.
SW1(config)#vlan 100
SW1(config-vlan)#no shutdown
SW1(config-vlan)#end
SW1#show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2
100 VLAN0100 active Fa0/3, Fa0/4
! Finally Ping is Working !!!
