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3725
June 4th, 2016 17:00
Routing outside the 6248
Alright, I know this is a basic question and I've done a bunch of looking around and hours worth of trying different configurations with this 6248. Here's what I'm faced with:
- I have a flat network at this point that is 192.168.1.0 /24.
- I have a cable gateway modem at 192.168.1.1 that I use to get northbound to the Internet which is NOT capable of setting static routes.
- DNS is a VM at 192.168.1.5.
- My 6248 has several VLANs, all of which I want to route between: 1, 5, 6, etc.
- I want from every VLAN to be able to get internet access through the said cable gateway.
- VLAN 1 is 192.168.1.0 /24 network.
- Switch interface for VLAN 1 is 192.168.1.25
- Switch interface for VLANs 5 and 6 are the .1 of their respective networks, so 192.168.5.1, etc.
- Switch management interface is on VLAN 250 with IP of 192.168.250.250 /24
- All existing and future VLANs will be simple /24 networks.
- Nothing is plugged into this 6248 right now while I get the configuration right, aside from an uplink cable (access port) into the 192.168.1.0 /24 network, and a test connection to an ESXi host where I'm testing different VLAN connectivity through a VM port group.
And now, questions/problems:
- Since on this switch you cannot route between the management interface VLAN, I had to create this on VLAN 250. So right now, I can't connect to the management interface, but I can connect to the interface at 192.168.1.25. Given my network right now, how/where should I configure this switch management interface? Or is it fine like it is?
- Because my cable modem gateway is at 192.168.1.1, if I'm testing connectivity from VLANs 5 or 6, while I can reach everything on VLAN 1 (including those hosts not directly connected to the 6248), I cannot go northbound to the internet. I have also put a default route in the switch for 192.168.1.1, but that isn't working. If I am connected to the 6248, configure a port group on VLAN 1, and set the gateway on a test VM to point to 192.168.1.25, I can get out to the internet. I can also ping the router interfaces for VLANs 5 and 6.
Here is my config:
!Current Configuration:
!System Description "PowerConnect 6248, 3.3.14.2, VxWorks 6.5"
!System Software Version 3.3.14.2
!Cut-through mode is configured as disabled
!
configure
vlan database
vlan 5-6,250
vlan routing 1 1
vlan routing 5 2
vlan routing 6 3
exit
stack
member 1 2
exit
ip address 192.168.250.250 255.255.255.0
ip address vlan 250
ip routing
ip route 0.0.0.0 0.0.0.0 192.168.1.1
interface vlan 1
routing
ip address 192.168.1.25 255.255.255.0
exit
interface vlan 5
name "test"
routing
ip address 192.168.5.1 255.255.255.0
exit
interface vlan 6
name "test"
routing
ip address 192.168.6.1 255.255.255.0
exit
username "admin" password db32549314c1390177c34647bf960343 level 15 encrypted
!
interface ethernet 1/g25
spanning-tree portfast
switchport mode trunk
switchport trunk allowed vlan add 1,5-6
exit
exit
daphnis
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June 6th, 2016 08:00
Thanks for your reply, Daniel. So you're saying that unless my cable modem gateway is able to configure static routes, that this basically won't work, correct?
daphnis
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June 6th, 2016 11:00
Let's assume for a moment that such a device was placed at 192.168.1.30 (so, on VLAN 1) as a virtual machine and that the 6248's interface at 192.168.1.25 still existed. Here are questions and assumptions I would ask to validate:
daphnis
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June 6th, 2016 13:00
Thanks again for the clarification, Daniel. As a last question, if a separate router *were* added into the picture with an existing cable modem/gateway and the 6248 switch functioning as L3, what would the "outside" interface be like versus the "inside" if the router is straddled entirely on VLAN 1?
The network as it sits now is very simple and, up to this point, has been completely flat. I am putting the 6248 into the picture in preparation for network virtualization, and to mimic a customer's datacenter network infrastructure. For this, I need a dedicated transport zone on its own VLAN, and additional VLANs are needed to simulate different sites for purposes of DR/BC testing.
daphnis
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June 7th, 2016 08:00
Thanks again, Daniel. I'm familiar with how such a device would work and the principles of it, just wasn't sure if its operation would work consistently with both legs in the same VLAN.
Let me run this scenario by you to see if return routing would work properly.
What if your cable modem/gateway you put on, say, VLAN 250 and set its IP as 192.168.250.2. You create VLAN 250 on the 6248, assign the switch's interface for that VLAN as 192.168.250.1, and plug an uplink from port g48 into the said cable modem/gateway setting it as an access port for VLAN 250. All other ports on the 6248 are trunk ports for various other VLANs except for 250. The default route on the switch is set for 192.168.250.2, thereby sending all traffic to that address if it doesn't have an internal path for it. If a host on VLAN 6 (ex., 192.168.6.26) attempts to communicate northbound to the Internet, it sends its packet to the gateway--the switch's interface of 192.168.6.1--and the switch in turn forwards that on to 192.168.250.2, the cable modem/gateway. Since VLAN 250 is only used for that one switch interface, it is forcing it to talk to the cable modem/gateway. Would return traffic from the Internet get routed properly back to 192.168.6.26? Or would this still not work?
Apologies for any frustration. I'm trying to determine what's the simplest way to make this work while keeping the network and infrastructure to a minimum.