Vlan – Losing connectivity after creating a VLAN other than the default VLAN

internetvlan

I have a 192.168.0.0/24 network that serves three computers. There are no issues with this part of the existing network.

I have purchased a new Cisco SG350-28P 28-Port Gigabit PoE Managed Switch.

I need this new switch to have a VLAN for two computers.

These two computers should be able to connect to the Internet through this new switch that is connected to the 192.168.0.0 network (so that the two computers can get Internet connection)

I need the new switch to have a network of 192.168.1.0/24 network.

Is it possible?  Can anyone help me?

The problem is that when the switch has a default VLAN 1 and I get an address like 192.168.0.99 from the existing network, then there is no issue getting Internet connection. The two computers get talking to each other as well as to the Internet. As soon as I make a new VLAN on the switch, the Internet connectivity is lost.

The current issue I am facing.

Losing Internet connectivity after creating a new VLAN for the two computers attached to this switch.

A heads up for those who are going to help. While this switch has an extensive CLI commands, but it is still limited. For examples, it does not support commands like, NAT or VTP.

Here is the relevant configuration of the Cisco SG350-28P when I do a SHOW RUN:

VLAN DATABASE
VLAN 5
EXIT
INTERFACE GigabitEthernet5
switchport mode access
switchport access vlan 5

.
.
.

The SHOW VLAN shows the following

Vlan    Name          Tagged Ports     Untagged Ports   Created by

---     ----          ------------     --------------   ---------

1        1                             gi1-28, Po1-8        DV

5        5                                                  S

I hope I was able to give the configuration that I was being asked about.

Network Diagram/Configuration

SG-350#sh vl
Created by: D-Default, S-Static, G-GVRP, R-Radius Assigned VLAN, V-Voice VLAN
Vlan       Name           Tagged Ports      UnTagged Ports      Created by
---- ----------------- ------------------ ------------------ ----------------
 1           1                            gi1-4,gi6-28,Po1-8        DV
 10         TEN                                  gi5                S

SG-350#sh ru
config-file-header
SG-350
v2.5.0.92 / RTESLA2.5_930_364_107
CLI v1.0
file SSD indicator encrypted
@
ssd-control-start
ssd config
ssd file passphrase control unrestricted
no ssd file integrity control
ssd-control-end cb0a3fdb1f3a1af4e4430033719968c0
!
!
unit-type-control-start
unit-type unit 1 network gi uplink none
unit-type-control-end
!
vlan database
vlan 10
exit
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e0bb 3Com_phone______________
bonjour interface range vlan 1
hostname SG-350
username CES password encrypted bb0f32698c29ea839a69da69fdb810b7005c219a 
privilege 15
clock summer-time EDT recurring usa
!
interface vlan 10
name TEN
!
interface GigabitEthernet5
 switchport access vlan 10
!
exit

Best Answer

You have some serious design problems. You must trunk both VLANs to the router, that means you will have a virtual interface for each VLAN, and you will need separate network addressing for each VLAN.

You cannot trunk through the unmanaged switch because it cannot be configured to trunk. You will need to move the connection from the unmanaged switch to the managed switch, and you will need to set up trunk configuration on both the managed switch and the router. The two VLANs will have separate addressing, so you either break the existing network into multiple networks, or you add a different network for new VLANs.

The router will need a virtual interface for each VLAN to be trunked across the link to the managed switch.

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