To size a firewall keep in mind these 3 main factors:
- Required throughput
- Features or additional packages
- Number and type of NIC (Network Interface Card) required
These 3 factors mainly affect RAM, CPU, mass memory and NIC quantities.
How to calculate throughput ?
A sum of available throughput of all interfaces [ including wan and lan / vlan etc ]
Firewall Ethernet Card -Top Cards.
| 1 GB Ethernet Card | 2.5 GB Ethernet Card | 10GbE (SFP+) NIC | 10GbE (10Gbase-T)-- backward compatible with 1GbE networks | 40GbE NIC | 100 GB | 
|---|---|---|---|---|---|
| Intel i350 (and Intel i354) | Intel 225 | Chelsio T520-SO-CR | Chelsio T520-BT | Chelsio T580-LP-CR | Intel E810-CQDA2 | 
| Intel i210 / Intel i211 | Intel 226 | Chelsio T520-CR | Intel X550-T2 | Chelsio T580-SO-CR | |
| Intel 82574L | Intel X710-da2 | Chelsio T420-BT | Intel XL710-qda2 | ||
| Intel X520-da2 / X520-sr2 | Intel X540-T2 | ||||
| Chelsio T420-CO-SR | |||||
| Chelsio T320-CO-SR | 
