VLAN Traffic is not passed between the Switches

[Sagar Patel]

Hello Everyone,

We have 3 Cisco switches in our network.

1. Cisco CBS350-24T-4G

2. Cisco CBS350-24P-4G

3. Cisco SG300-28P

Kindly check attached image file of topology.

We have two VLANs- V156 & V157. We have manually created these vlans on all three switches.

Between the switches , we have configured LAG ports.

Issue is on Cisco SG300-28P switch (SW3). Devices connected to this switch can not communicate with the devices connected on Cisco CBS350-24P-4G (SW2) and also with the gateway IP 192.168.156.250 (firewall's VLAN interface).

Gateway firewall has DHCP pool of 192.168.156.0/24. Computers connected to Cisco CBS350-24P-4G (SW2) are getting IP from DHCP pool on firewall.

But computers connected to Cisco SG300-28P switch (SW3) are getting IP address from DHCP. I tried with manual IP address on the computer and attempted ping to 192.168.156.250 -- gateway IP. But it failed.

Please help.

With regards,

Sagar C. Patel

[marce1000]

 - Have you also configured trunk ports on the switches, in order to connect the vlans on the devices (where needed).

 M.

[Sagar Patel]

Yes, on SW-1 (Cisco CBS350-24T), I have done that. But on SW-3 (Cisco SG300-2P), I applied "switchport mode trunk" command but it is not showing in to the configuration.

[paul driver]

Hello
Enable ip routing on the CB350-24T-G

[balaji.bandi]

But computers connected to Cisco SG300-28P switch (SW3) are getting IP address from DHCP. I tried with manual IP address on the computer and attempted ping to 192.168.156.250 -- gateway IP. But it failed.

is your device getting IP from DHCP ? what IP address getting ? are you able to ping FW gateway IP ?

when you configure manually what is the IP you configured,  ?

if both Sw2 and SW3 are using same VLAN, then I do not see reason, until end device have FW build in ?

[Sagar Patel]

SORRY..!

"But computers connected to Cisco SG300-28P switch (SW3) are NOT getting IP address from DHCP. I tried with manual IP address on the computer and attempted ping to 192.168.156.250 -- gateway IP. But it failed.

[Sagar Patel]

Hello Everyone,

Kindly check the attached images. Both images show the trunk status of two switches.

I am facing issue on the host connected to Cisco SG300 switch.

- Firewall is the gateway device with VLAN sub-interfaces.

- Firewall has the DHCP pool for VLAN 156 - 192.168.156.0/24 network.

- Hosts connected on Cisco CBS350-24P (SW2), are getting IP address from that pool on firewall.

- Hosts (in VLAN 156) connected on Cisco SG300-28P(SW-3) are not getting IP address from the DHCP pool on firewall.

- On the hosts connected to SG300-28P, I assigned manual IP(192.168.156.220) from 192.168.156.0/24 subnet, but still that PC is unable to ping gateway (firewall's IP - 192.168.156.250)

Thank you and regards,

Sagar Patel

[amikat · Accepted solution]

Hi,

Contrary to CBS350 where by default, trunk ports belongs to all created VLANs with SG300 box by default, trunk ports belongs to the default VLAN only. Will you please configure "switchport trunk allowed vlan add 156,157" at your SG300 trunk ports (gi23,gi24) and check if there is any progress.

Best regards,

Antonin

[Sagar Patel]

Thank you so much. Applied that command on SG300 and it worked!

Regards,

Sagar Patel

[NetworkDave]

@Sagar Patel,

I was going suggest checking and providing the output:
Cisco SG300-28P switch (SW3)
-show interfaces switchport g23
-show interfaces switchport g24
before recommending configuration changes.

Someone was a little quicker. Please make the changes given by @amikat and retest.

HTH
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[Sagar Patel]

Hello, Kindly check attached snapshots of output.

Regards.

Sagar Patel