IP address problem on VLAN and VLAN interfaces

[lorn10]

Here follows a new question. How can I assign an IP address of the same subnet to a VLAN and the corresponding VLAN interface?

It doesn't work in my case. Well, there are some config examples available which indicates that this should be possible. I get always the message Error: The IP address you entered overlaps with another interface

Vlan-interface1 should have:

ip address 192.168.1.254 255.255.255.0

This fails because the corresponding vlan1 GigabitEthernet2/0 interface has:

ip address 192.168.1.1 255.255.255.0

The idea is to connect vlan1 and vlan2 with the following static route:

ip route-static 192.168.2.0 255.255.255.0 192.168.1.254

GigabitEthernet2/0.2 (a sub interface) belongs to vlan2, it has:

ip address 192.168.2.2 255.255.255.0

Vlan-interface2 should have:

ip address 192.168.2.1 255.255.255.0

But also here I get the same Error: The IP address you entered overlaps with another interface message.

[parnassus · Accepted solution]

Hi! If your requirement is to route VLAN 1 and VLAN 2 (isn't it?) generally it's enought to work with VLAN interfaces (SVI), applying desired non overlapping IP Addresses (e.g. VLAN 1 SVI: 192.168.1.254 and VLAN 2 SVI: 192.168.2.254) and enabling IPv4 Routing (ip routing)...this way VLAN 1 and VLAN 2 will be routed through their SVI IP Addresses (no static route(s) are necessary since both SVI are directly connected to the L3 Switch they belong). Or are you trying to route the GigabitEthernet2/0 (192.168.1.1) and the sub-inteface GigabitEthernet2/0.2 (192.168.2.2)?

[lorn10]

Hi parnassus!

Thanks for your response. Well, you are right, the effective requirement is not to route between VLAN1 and VLAN2 but I need access to the VoIP (FreePBX) Server (192.168.2.4) in VLAN2 from VLAN1 (192.168.1.x).

As I explained in my other “Comware config migration” thread, I want to separate all the IP phones, totally up to 25, into VLAN2. In consequence, also the VoIP Server needs to be in that VLAN2.

The VLAN1 remains the main group which contains all the other stuff.

Finally there will be also a VLAN3 but this is only for the guest WiFi SSID.

Will rethink my “implementation” and follow your advice.

[lorn10]

A final comment, - it turned out that the situation is the other way around.

Regarding the above mentioned config examples I can confirm (to my big surprise) that the inter vlan routing is working out of the box. So no additional setting and no additional static route is necessary.

In my case this is okay for VLAN1 and VLAN2 but not for VLAN3.

So, as I said, the whole context has changed and now I must find out how I can isolate VLAN3 from the other two.

More information about the corresponding topology can be found in my other thread: https://community.hpe.com/t5/comware-based/config-migration-from-comware-3-to-comware-5-and-later-to/td-p/7086562

[parnassus]

---

@lorn10 wrote: Regarding the above mentioned config examples I can confirm (to my big surprise) that the inter vlan routing is working out of the box. So no additional setting and no additional static route is necessary.

The fact is that on Comware once you assign an IP address to a VLAN interface you're automatically including that SVI into the group of VLANs that will be routed by the Switch. Static routes aren't necessarily involved at that point since the IPv4 Routing feature of the L3 Switch is enough to route traffic between involved VLANs.

---

@lorn10 wrote: In my case this is okay for VLAN1 and VLAN2 but not for VLAN3.

So, as I said, the whole context has changed and now I must find out how I can isolate VLAN3 from the other two.

 It's a matter of configure ACLs (Access Control Lists) so you can decide who can/can't go where to do what.