Does the ipfs private network support NAT traversal?

I deployed an ipfs private network with two nodes behind different routers. They can’t connect to each other.
use “ipfs dht findpeer ”

/ip4/A.A.A.A/tcp/4001/p2p/12D3KooWHa3MM3qm2bT1NjLVWDZTJu5onQaTFyVoLQroFtVi1tj7
/ip4/A.A.A.A/tcp/4001/p2p/12D3KooWHa3MM3qm2bT1NjLVWDZTJu5onQaTFyVoLQroFtVi1tj7/p2p-circuit/p2p/12D3KooWGFUKErwnnbm8z47hgoTXFLCjjzGjDQEc6FwF8wgiPKVS

then use ipfs swarm peers. can find /ip4/A.A.A.A/tcp/4001/p2p/12D3KooWHa3MM3qm2bT1NjLVWDZTJu5onQaTFyVoLQroFtVi1tj7/p2p-circuit/p2p/12D3KooWGFUKErwnnbm8z47hgoTXFLCjjzGjDQEc6FwF8wgiPKVS

but when I use. ipfs get cid.( this cid comes from a node behind another router ) can’t success. then the p2p-circuit connection also broke.

You will need a few public reachable nodes to use as relays (used for signaling), but yes it should work. (with usual caveats that this depends on your routers and network)