### **Comprehensive Project Plan for VLAN Bridging with mDNS Proxy and Avahi Servers** --- ### **1. Project Overview** **Objective**: Enable Apple devices in VLAN 15 and 19 to discover Apple TVs in VLAN 7 via Bonjour (mDNS) **without** requiring Layer 3 switches or VLAN routing on the Sophos firewall. **Key Requirements**: - **VLANs**: Student (15), Teacher (19), AppleTV (7). - **Subnets**: - VLAN 15: `172.16.19.254/255.255.252.0` - VLAN 19: `192.168.151.254/255.255.252.0` - VLAN 7: `172.16.111.254/255.255.248.0` - **Services**: Bonjour (mDNS), HTTP/HTTPS (80,443), DHCP (546/udp, 547/udp), and other protocols. - **Tools**: - **Sophos XGS4300**: DHCP server, firewall. - **ESXi**: Hypervisor for VMs. - **Debian VMs**: Avahi servers, mDNS proxy. - **Switches**: Level 2 (no IGMP snooping). - **VM IPs**: `.250` in each VLAN (e.g., `172.16.19.250`, `192.168.151.250`, `172.16.111.250`). --- ### **2. Network Architecture Design** #### **A. VLAN Configuration (ESXi vSwitch)** - **vSwitch Setup**: - Create a **vSwitch** (e.g., `vSwitch0`) with **VLAN tags** for each VLAN (15, 19, 7). - Assign **VMs** to this vSwitch with appropriate VLAN tags. - **VM Interfaces**: - Each **Avahi server VM** and **mDNS proxy VM** will have **one virtual NIC per VLAN** (e.g., VLAN 15, VLAN 19, VLAN 7). - Ensure **untagged interfaces** for management (optional). #### **B. VM Resource Allocation** - **Avahi Server VMs**: - **RAM**: 1GB (minimal, as Avahi is lightweight). - **CPU**: 1 core. - **Storage**: 10GB (for OS and logs). - **mDNS Proxy VM**: - **RAM**: 2GB (to handle traffic forwarding). - **CPU**: 2 cores. - **Storage**: 20GB (for logs and configurations). #### **C. IP Addressing** - **Avahi Servers**: - VLAN 15: `172.16.19.250` - VLAN 19: `192.168.151.250` - VLAN 7: `172.16.111.250` - **mDNS Proxy**: - Assign a **static IP** (e.g., `172.16.111.251`) in VLAN 7 (or use a management VLAN if needed). --- ### **3. Software and Configuration** #### **A. Avahi Servers (Per VLAN)** - **OS**: Debian 12 (Bookworm). - **Installation**: ```bash apt update && apt install avahi-daemon avahi-utils ``` - **Configuration (`/etc/avahi/avahi-daemon.conf`)**: - Ensure `host-name` is set to the VM's hostname (e.g., `avahi15`). - Set `domain-name` to the local domain (e.g., `local`). - **Service Announcement**: - Place service files in `/etc/avahi/services/` for Apple TVs (e.g., `apple-tv.service`). - Example `apple-tv.service`: ```xml _http._tcp _apple-tv._sub 80 apple-tv.local ``` #### **B. mDNS Proxy (VM)** - **Software**: Use **`mdnsproxy`** (not `dnsmasq`) for mDNS forwarding. - **Installation**: ```bash apt update && apt install mdnsproxy ``` - **Configuration (`/etc/mdnsproxy.conf`)**: - Define **forwarding rules** between VLANs: ```ini [forward] 172.16.19.250 192.168.151.250 172.16.111.250 192.168.151.250 172.16.19.250 172.16.111.250 172.16.111.250 172.16.19.250 192.168.151.250 ``` - Ensure **UDP port 5353** is open for mDNS traffic. - **Firewall Rules (Sophos XGS)**: - Allow **UDP port 5353** between VLAN 15, 19, and 7. - Allow **TCP/UDP ports 80, 443, 546, 547** for service access. --- ### **4. Firewall Configuration (Sophos XGS4300)** - **DHCP Server**: - Assign IPs to VLANs 15, 19, and 7. - Ensure **IP ranges** match the subnets (e.g., VLAN 15: `172.16.19.252-254`). - **Firewall Rules**: - **Allow** traffic between VLANs 15, 19, and 7 via the mDNS proxy. - **Deny** direct communication between VLANs (to enforce proxy routing). - **Allow** **UDP 5353** and **TCP/UDP 80, 443, 546, 547** for service discovery and access. --- ### **5. Testing and Validation** - **Step 1**: Verify **VLAN tagging** on ESXi vSwitch. Use `ovs-ofctl dump-ports` to confirm VLAN tags. - **Step 2**: Test **mDNS traffic** with `tcpdump` on the mDNS proxy VM: ```bash tcpdump -i eth1 port 5353 ``` - **Step 3**: Use **Bonjour tools** (e.g., `dns-sd`) to discover services: ```bash dns-sd -B _http._tcp local ``` - **Step 4**: Ensure **Apple devices** can access services via the proxy. - **Step 5**: Monitor **firewall logs** for denied traffic to confirm proxy routing. --- ### **6. Potential Hurdles and Solutions** | **Hurdle** | **Solution** | |------------|--------------| | **Level 2 Switches**: No IGMP Snooping | **mDNS proxy** bridges VLANs, so multicast traffic is handled by the proxy. | | **Firewall Rules**: Blocking inter-VLAN traffic | **Allow traffic via the proxy** (UDP 5353) and ensure services are accessible via ports 80, 443, etc. | | **VM IP Conflicts** | Assign **static IPs** in each VLAN (e.g., `.250`) to avoid DHCP conflicts. | | **mDNS Proxy Not Forwarding** | Verify `mdnsproxy` configuration and ensure VMs are connected to all VLANs. | | **Service Discovery Failures** | Test with `dns-sd` and ensure Avahi servers are correctly configured. | --- ### **7. Resource Recommendations** - **ESXi Host**: - At least 8GB RAM, 4 cores. - Ensure **vSwitch** is configured with VLAN tags. - **VMs**: - **Avahi Servers**: 1GB RAM, 1 core. - **mDNS Proxy**: 2GB RAM, 2 cores. - **Storage**: - Allocate 10-20GB per VM for OS, logs, and service files. --- ### **8. Final Notes** - **Scalability**: Add more Avahi servers if needed, but ensure the mDNS proxy can handle increased traffic. - **Monitoring**: Use **Prometheus/Grafana** to monitor traffic and resource usage. - **Documentation**: Document VLAN IPs, VM configurations, and firewall rules for future maintenance. --- ### **9. Has Anything Been Missed?** - **No**: All requirements are addressed, including VLAN isolation, mDNS bridging, and service accessibility. - **Optional Enhancements**: - Add **load balancing** for the mDNS proxy. - Use **SNMP** to monitor switch traffic. - Implement **failover** for critical services. --- ### **10. Conclusion** This setup is **feasible** and **robust** for your requirements. The key is ensuring the **mDNS proxy** is correctly connected to all VLANs via the ESXi vSwitch, and the **Sophos firewall** allows only traffic via the proxy. With proper testing and configuration, Apple devices in VLANs 15 and 19 will discover Apple TVs in VLAN 7 via Bonjour, and services will be accessible via the required ports. 🚀