NAT/PAT Table Visualizer

Simulate PAT overload mappings, calculate NAT table capacity, and visualize port exhaustion thresholds.

Number of Inside Hosts

Outside IPs (PAT pool size)

Avg Simultaneous Sessions per Host

Protocol

PAT Capacity Results

PAT Entry Simulator

Simulate adding NAT entries to see the translation table grow.

Inside Local IP

Inside Local Port

Outside Global IP

Destination IP:Port

NAT Translation Table

Port Exhaustion Reference

Platform	PAT Port Range	Ports per IP	Max Translations
Cisco IOS/IOS-XE	1024–65535	64,512	64,512 × outside IPs
Cisco ASA	1024–65535 (default)	64,512	Limited by xlate table memory
Linux iptables/nftables	1024–65535 (default)	64,512	Limited by conntrack table size
Windows Server NAT	1025–5000 (legacy) / 1024–65535	63,511	Registry-tunable
RFC 4787 (BEHAVE)	Recommends preserving source port	—	Per-endpoint mapping