Am new here, not a networking expert, but know enough to explain the situation and hopefully get some assistance.
We have moved into new offices and have some new Level 3 PoE switches that we are using for both DATA (VLAN1) and VOICE (VLAN2). Nothing complicated. Both VLANs are working nicely as isolated networks. In addition we have an Adtran 3448 which has acted as our firewall and gateway to the outside for years. Allows for VPN access and access to some internal servers (webmail, etc).
Now we want the Adtran 3448 to act as a go-between for traffic between the two VLANs. For instance, the phone system server is on VLAN2. If I want to access the web interface of this server, which has an IP 10.115.0.x I can;t because my workstation is on 128.127.126.x.
So we set up a physical interface switchport 0/8 which has an IP 10.115.0.1 and have wired this into the Level 3 switch. I can ping 10.115.0.1 no problem but anything beyond the Adtran in VLAN2 is not reachable.