Problems with Switch Small Business SG220 and Grandstream gxw4108 gateway

[gasuton]

Hi everyone, i have a 3CX system working with Grandstream equipments, everything is connected to some Switches from the Small Bussines line model SG220, the only exeption is the gxw4108 gateway, this is conected directly to the ISP modem becuse if i conected directly to the switch the SIP accounts doesn't connect to 3CX. Just as a note, the Switches are connected in cascade and the main one is connected to the ISP modem.

So i think the problem is in my Cisco switch that are blocking something, but i don't know what could it be because we didn't set anything yet, they are setted as they came from factory.

If anybody can help me with this i will really appreciate, because i can not connect the gxw4108 gateway to the ISP modem anymore.

[pieterh]

without additional information we can only guess what's happening

can you provide an  overview of IP-addresses in use?

and for what reason you "can not connect the gxw4108 gateway to the ISP modem anymore"

[Richard Burts]

I agree that we do not have enough information about this situation to be able to really determine what is the problem and how to fix it. Based on the little information that we do have I would offer these comments

- if the switches are just as they came from the factory then all of the ports are access ports and in the default vlan. How do the devices that are connected to the switches get their IP address?

* Is there a DHCP server that we have not been told about?

* Are the devices manually configured with IP address, mask, and default gateway? If so what are the addresses and what is the gateway?

* or are the devices attempting DHCP, not getting assigned an address, and defaulting to addresses in 169.254 network?

* understanding the IP addressing would be the first step in identifying the problem.

- assuming that the connected devices are using some type of private IP addressing then something would need to perform address translation to be able to access resources in the Internet. I am sure that the SG220 does not support address translation. So is anything doing address translation?

Please provide more details about this situation.