If the MFP is enabled, AllPeers uses STUN for discovering network situation of peers. One of performed tests is the detection of most restrictive NAT between peer and the internet. Detected value is written to logs in format ‘NAT detected : <number>’ where <number> depicts one of the following :
| Number | NAT Type |
| 0 | Unknown |
| 1 | None |
| 2 | Full Cone |
| 3 | Restricted |
| 4 | Port Restricted |
| 5 | Symmetric Firewall |
| 6 | Symmetric |
| NAT Model | Detected | Users |
| FRITZ!Box Fon WLAN 7050 | 6 | Ondrej |
| Linksys WRT54GS running DD-WRT v23 SP2 (09/15/06) std | 6 | micxer |
