Port not working for access to vlan

[ACarter51016]

The senior IT person for our company recently passed away from, wait for it, COVID-19. I have been tasked with taking over.

I am the network and hardware guy but I didn't handle any of the Cicso we have. I don't have a lot of experience with it but I am learning now. I have researched this for about 2 weeks now and haven't had any success. We are adding an industry-specific piece of equipment that must be on the correct vlan. 

The switch is a 3750x.

The issue I am having is using a single open port on the switch. We have 3 vlans:

10.2.0.0
10.2.2.0
10.2.3.0

When I plug into this port, I get an address from the DHCP server on 10.2.2.0

I want the port to be on the 10.2.0.0 vlan and I thought I was successful in adding it. But even after that, I get an address from the 10.2.2.0 network and can't access anything on the 10.2.0.0 vlan.

However, the devices on the 10.2.0.0 vlan are able to communicate with the 10.2.2.0. Just this port can't do it. 

My goal is to make this port on the 10.2.0.0 vlan and successfully communicate with both the 10.2.0.0 and 10.2.2.0 networks.

How can I check this and find what is causing this from happening? I really appreciate it.

[balaji.bandi]

here is the simple steps to follows :

1. Login to switch.

2. issue command  show IP interface brief, you get VLAN associated with IP address.

3., if you looking to get the device 10.2.0.0 - not the VLAN with above mentioned command what VLAN

4. you decide which port you like to have that IP addres to assinged to device.

do below steps :

config t 

interace gi x/x - x/x where the port connected to device.

switchport mode acces

switchport access vlan XX - whre the VLAN noted above

!

end

connect the device and test it, same rule for other IP address and VLAN, change the VLAN number

do 1 or 2 device you will get to know automatically

if still difficult post complete config and tell what port you like what IP we can suggest.

[Richard Burts]

We don't have much detail to work with and that impacts our ability to give good advice. As a start can you provide this information:

- is inter vlan routing done on the 3750 or on some other device?

- please post the output of show ip route from the switch. 

- what port on the switch is the PC plugged into?

- what IP address, mask, and gateway does the PC have?

- please post the output of show interface status from the switch. 

- please post the output of show ip interface brief from the switch. 

[ACarter51016]

Hello Richard, thank you for the replay. I have included the information below.

Please let me know if you need anything else.  

- is inter vlan routing done on the 3750 or on some other device?

At this point, that is unknown. I am still moving through everything as the previous person didn't leave any notes behind before his death. But I do believe it's done on the switch 

- please post the output of show ip route from the switch. 
show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is 10.2.2.1 to network 0.0.0.0

C 10.2.0.0/24 is directly connected, Vlan9
C 10.2.2.0/24 is directly connected, Vlan2
C 10.2.3.0/24 is directly connected, Vlan3
S* 0.0.0.0/0 [1/0] via 10.2.2.1

- what port on the switch is the PC plugged into?
Gi1/0/20

- what IP address, mask, and gateway does the PC have?
IP 10.2.0.10/255.255.255.0 GW - 10.2.0.1 statically assigned 

- please post the output of show interface status from the switch. 

show interface status

Port Name Status Vlan Duplex Speed Type
Gi1/0/1 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/2 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/3 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/4 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/5 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/6 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/7 connected 2 a-full a-100 10/100/1000BaseTX
Gi1/0/8 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/9 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/10 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/11 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/12 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/13 connected 9 a-full a-1000 10/100/1000BaseTX
Gi1/0/14 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/15 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/16 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/17 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/18 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/19 connected 2 a-full a-100 10/100/1000BaseTX
Gi1/0/20 notconnect 9 auto auto 10/100/1000BaseTX
Gi1/0/21 connected 2 a-full a-100 10/100/1000BaseTX
Gi1/0/22 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/23 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/24 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/25 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/26 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/27 connected 2 a-full a-10 10/100/1000BaseTX
Gi1/0/28 connected 1 a-full a-1000 10/100/1000BaseTX
Gi1/0/29 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/30 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/31 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/32 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/33 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/34 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/35 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/36 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/37 connected 9 a-full a-1000 10/100/1000BaseTX
Gi1/0/38 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/39 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/40 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/41 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/42 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/43 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/0/44 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/45 notconnect 2 auto auto 10/100/1000BaseTX
Gi1/0/46 notconnect 9 auto auto 10/100/1000BaseTX
Gi1/0/47 connected 1 a-full a-1000 10/100/1000BaseTX
Gi1/0/48 connected 2 a-full a-1000 10/100/1000BaseTX
Gi1/1/1 connected trunk a-full a-1000 1000BaseSX SFP
Gi1/1/2 connected trunk a-full a-1000 1000BaseSX SFP
Gi1/1/3 notconnect 1 auto auto Not Present
Gi1/1/4 notconnect 1 auto auto Not Present
Po1 connected trunk a-full a-1000
Po20 notconnect unassigned auto auto
Fa0 disabled routed auto auto 10/100BaseTX

- please post the output of show ip interface brief from the switch. 
show ip interface brief
Interface IP-Address OK? Method Status Protocol
Vlan1 unassigned YES NVRAM administratively down down
Vlan2 10.2.2.2 YES NVRAM up up
Vlan9 10.2.0.1 YES NVRAM up up
Vlan3 10.2.3.1 YES NVRAM up up
FastEthernet0 unassigned YES NVRAM administratively down down
GigabitEthernet1/0/1 unassigned YES unset down down
GigabitEthernet1/0/2 unassigned YES unset up up
GigabitEthernet1/0/3 unassigned YES unset up up
GigabitEthernet1/0/4 unassigned YES unset down down
GigabitEthernet1/0/5 unassigned YES unset down down
GigabitEthernet1/0/6 unassigned YES unset down down
GigabitEthernet1/0/7 unassigned YES unset up up
GigabitEthernet1/0/8 unassigned YES unset up up
GigabitEthernet1/0/9 unassigned YES unset down down
GigabitEthernet1/0/10 unassigned YES unset up up
GigabitEthernet1/0/11 unassigned YES unset up up
GigabitEthernet1/0/12 unassigned YES unset down down
GigabitEthernet1/0/13 unassigned YES unset up up
GigabitEthernet1/0/14 unassigned YES unset down down
GigabitEthernet1/0/15 unassigned YES unset up up
GigabitEthernet1/0/16 unassigned YES unset down down
GigabitEthernet1/0/17 unassigned YES unset up up
GigabitEthernet1/0/18 unassigned YES unset down down
GigabitEthernet1/0/19 unassigned YES unset up up
GigabitEthernet1/0/20 unassigned YES unset down down
GigabitEthernet1/0/21 unassigned YES unset up up
GigabitEthernet1/0/22 unassigned YES unset up up
GigabitEthernet1/0/23 unassigned YES unset down down
GigabitEthernet1/0/24 unassigned YES unset down down
GigabitEthernet1/0/25 unassigned YES unset up up
GigabitEthernet1/0/26 unassigned YES unset down down
GigabitEthernet1/0/27 unassigned YES unset up up
GigabitEthernet1/0/28 unassigned YES unset up up
GigabitEthernet1/0/29 unassigned YES unset down down
GigabitEthernet1/0/30 unassigned YES unset up up
GigabitEthernet1/0/31 unassigned YES unset down down
GigabitEthernet1/0/32 unassigned YES unset down down
GigabitEthernet1/0/33 unassigned YES unset up up
GigabitEthernet1/0/34 unassigned YES unset up up
GigabitEthernet1/0/35 unassigned YES unset down down
GigabitEthernet1/0/36 unassigned YES unset up up
GigabitEthernet1/0/37 unassigned YES unset up up
GigabitEthernet1/0/38 unassigned YES unset up up
GigabitEthernet1/0/39 unassigned YES unset up up
GigabitEthernet1/0/40 unassigned YES unset up up
GigabitEthernet1/0/41 unassigned YES unset down down
GigabitEthernet1/0/42 unassigned YES unset down down
GigabitEthernet1/0/43 unassigned YES unset up up
GigabitEthernet1/0/44 unassigned YES unset down down
GigabitEthernet1/0/45 unassigned YES unset down down
GigabitEthernet1/0/46 unassigned YES unset down down
GigabitEthernet1/0/47 unassigned YES unset up up
GigabitEthernet1/0/48 unassigned YES unset up up
GigabitEthernet1/1/1 unassigned YES unset up up
GigabitEthernet1/1/2 unassigned YES unset up up
GigabitEthernet1/1/3 unassigned YES unset down down
GigabitEthernet1/1/4 unassigned YES unset down down
Te1/1/1 unassigned YES unset down down
Te1/1/2 unassigned YES unset down down
Port-channel1 unassigned YES unset up up
Port-channel20 unassigned YES unset down down

[Georg Pauwen]

Hello,

judging from the output:

--> Gi1/0/20 notconnect 9 auto auto 10/100/1000BaseTX

the port is in the wrong Vlan. Make sure the configuration looks like below:

interface GigabitEthernet1/0/20

switchport mode access

switchport access vlan 2

spanning-tree portfast

[ACarter51016]

I apologize for my lack of understanding on this. 

If we do that, it will move it to vlan2 right? We want it on vlan9 though. 

What is strange to me is that even though the device is plugged in, the status still says unconnected. 

[Richard Burts]

There are several things to address. 

- it appears that @Georg Pauwen  understands the requirements differently than I do. If I understand the original post correctly you want the device to have an IP address in 10.2.0.0 subnet which is vlan 9. So I am puzzled that he puts it in vlan 2. 

- the output does indicate that your 3750 is doing inter vlan routing. 

- if I understand the original post correctly when you plugged a device in that port using DHCP it received an IP in 10.2.2.0 which is vlan 2. This suggests that perhaps it is not really in 1/0/20 but is in some port that is in vlan 2. That would also explain why the output shows the port 1/0/20 as not connected. 

One way way to check (if you are able to login on the switch and to look at syslog messages) would be to disconnect the port, reconnect the port, and then to look for syslog messages about a port that went down and then came back up. 

[Georg Pauwen]

Hello,

my bad, I misread the output. Richard's suggestion that it is connected to a port other than 1/0/20 is likely the problem here....good catch !

[Richard Burts]

Thanks for the clarification. No problem. It happens to all of us from time to time. 

[ACarter51016]

- if I understand the original post correctly when you plugged a device in that port using DHCP it received an IP in 10.2.2.0 which is vlan 2. This suggests that perhaps it is not really in 1/0/20 but is in some port that is in vlan 2. That would also explain why the output shows the port 1/0/20 as not connected. 

Correct. We have made sure the device is on vlan9 but it receives an address from vlan2. Right now we have a laptop plugged into it and the laptop gets an address from the vlan2 pool. If we set the IP statically to the vlan9 addresses, it won't allow any traffic. 

[Georg Pauwen]

Hello,

not sure if that has already been asked, but what do you use as DHCP server ? Is that an external device and if so, what is the IP address of that DHCP server ?

[Richard Burts]

Thanks for the information. I find these facts to be contradictory:

- you have a device plugged in and you believe it is on g1/0/20 in vlan 9. 

- when a device is plugged into the port and uses DHCP it gets an address in vlan 2. 

- the output of show interface status indicates that 1/0/20 is not connected. 

I believe that these things suggest that the device is plugged into some other port. Please do the test I suggested of disconnect the device, reconnect the device and post log messages about port going down and back up. 

[paul driver]

Hello
When you say the laptop cannot ping anything does that also mean hosts in the same vlan?
Have you created the vlan9 on the switch because a port on a vlan that doesn't exist on the switch won't come active 

As for dhcp does a scope exist on the server for that vlan and if this server resides off the lan you may well require a relay address on the l3 interfaces for the broadcast requests 

For just connectivity try defaulting the port and reapplying the vlans on the switch then text again if that works with a static addressing then you may need to apply a relay address for dhcp and validate a scope does exist for vlan 9

default inter x/x
int x/x
switchport host
switchport mode access
switchport access vlan 9
no shut

exit

vlan 2,3,9
exit

[ACarter51016]

Thank you all for the excellent advise and guidance.  Unfortunately, we are still getting IP's from VLAN 2.  

we are showing that we are connected and assigned vlan 9.  See below please.

Gi1/0/20 connected 9 a-full a-1000 10/100/1000BaseTX

show int gi1/0/20
GigabitEthernet1/0/20 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 6c41.6a35.db94 (bia 6c41.6a35.db94)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:31, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
3686 packets input, 996965 bytes, 0 no buffer
Received 1498 broadcasts (1242 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 1242 multicast, 0 pause input
0 input packets with dribble condition detected
6407430 packets output, 1406103564 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out

I thank you in advance for any additional advise on this issue.

[Richard Burts]

If it is connected in G1/0/20 it is strange that it is getting IP in vlan 2. Can you tell us what you have done to verify that your device is really connected in G1/0/20? Can you post the configuration of that interface?