I am making an attempt to know how Lightning works by working checks utilizing Bitcoin Core on my native machine in REGTEST mode along with working two LND Lightning nodes (let’s name them the basic Bob & Alice) on separate localhost ports too. I am utilizing bitcoin-cli and lncli to interface with the nodes.
I made Alice’s LN hook up with Bob’s LN and opened a channel between them with an preliminary capability of 10,000,000 sats, funded by Alice’s chain pockets, and included a --pushamt of 35,000 sats to Bob’s LN with the intention to create some inbound liquidity. This all appeared to have labored simply effective and as anticipated, and the funding transaction right into a 2of2 Multisig masking the channel was added into the blockchain too (6 confirmations).
Nonetheless, one thing’s however flawed. Regardless of Alice having despatched out BTC on the channel, Bob can not ship any of that BTC again to Alice! I even had Bob ship Alice an bill for an additional 5,000 sats, however nothing modified after she paid it (apart from a rise in her distant steadiness to 40,000 sats)—still Bob nonetheless can not ship her even 1 sat utilizing the channel’s inbound liquidity! I am simply not understanding why that’s.
Session standing from Alice’s perspective (native/distant is reversed for Bob, after all):
$ lncli --lnddir=lnd_alice -n regtest openchannel --connect 127.0.0.1:9736 --node_key 030fb4423c15e3e049dbbdc646d0ef3ab7450a891652bbe0c39a14a8f5b44dc15f --sat_per_vbyte 1 --local_amt 10000000 --push_amt 35000 --block --base_fee_msat 1000 --fee_rate_ppm 10 --min_confs 1
{
"funding_txid": "df79c5246a3f1f8dfd6c983106b743a8220a1f4c819b76aeb41d69ccfc2baf4e"
}
{
"channel_point": "df79c5246a3f1f8dfd6c983106b743a8220a1f4c819b76aeb41d69ccfc2baf4e:0"
}
$ lncli --lnddir=lnd_alice -n regtest listchannels
{
"channels": [
{
"active": true,
"remote_pubkey": "030fb4423c15e3e049dbbdc646d0ef3ab7450a891652bbe0c39a14a8f5b44dc15f",
"channel_point": "df79c5246a3f1f8dfd6c983106b743a8220a1f4c819b76aeb41d69ccfc2baf4e:0",
"chan_id": "513471930236928",
"capacity": "10000000",
"local_balance": "9961530",
"remote_balance": "35000",
"commit_fee": "2810",
"commit_weight": "1116",
"fee_per_kw": "2500",
"unsettled_balance": "0",
"total_satoshis_sent": "0",
"total_satoshis_received": "0",
"num_updates": "0",
"pending_htlcs": [],
"csv_delay": 1201,
"non-public": false,
"initiator": true,
"chan_status_flags": "ChanStatusDefault",
"local_chan_reserve_sat": "100000",
"remote_chan_reserve_sat": "100000",
"static_remote_key": false,
"commitment_type": "ANCHORS",
"lifetime": "80",
"uptime": "80",
"close_address": "",
"push_amount_sat": "35000",
"thaw_height": 0,
"local_constraints": {
"csv_delay": 1201,
"chan_reserve_sat": "100000",
"dust_limit_sat": "354",
"max_pending_amt_msat": "9900000000",
"min_htlc_msat": "1",
"max_accepted_htlcs": 483
},
"remote_constraints": {
"csv_delay": 1201,
"chan_reserve_sat": "100000",
"dust_limit_sat": "354",
"max_pending_amt_msat": "9900000000",
"min_htlc_msat": "1",
"max_accepted_htlcs": 483
},
"alias_scids": [],
"zero_conf": false,
"zero_conf_confirmed_scid": "0",
"peer_alias": "unable to lookup peer alias: alias for node not discovered",
"peer_scid_alias": "0",
"memo": ""
}
]
}
$ lncli --lnddir=lnd_alice -n regtest channelbalance
{
"steadiness": "9961530",
"pending_open_balance": "0",
"local_balance": {
"sat": "9961530",
"msat": "9961530000"
},
"remote_balance": {
"sat": "35000",
"msat": "35000000"
},
"unsettled_local_balance": {
"sat": "0",
"msat": "0"
},
"unsettled_remote_balance": {
"sat": "0",
"msat": "0"
},
"pending_open_local_balance": {
"sat": "0",
"msat": "0"
},
"pending_open_remote_balance": {
"sat": "0",
"msat": "0"
}
}
$ lncli --lnddir=lnd_alice -n regtest getchaninfo --chan_point "df79c5246a3f1f8dfd6c983106b743a8220a1f4c819b76aeb41d69ccfc2baf4e:0"
{
"channel_id": "513471930236928",
"chan_point": "df79c5246a3f1f8dfd6c983106b743a8220a1f4c819b76aeb41d69ccfc2baf4e:0",
"last_update": 1733192887,
"node1_pub": "030fb4423c15e3e049dbbdc646d0ef3ab7450a891652bbe0c39a14a8f5b44dc15f",
"node2_pub": "03f23e9d775b5363a2311742209fc4d50eb47e8c226b78472609356f9d72294729",
"capability": "10000000",
"node1_policy": {
"time_lock_delta": 80,
"min_htlc": "1000",
"fee_base_msat": "1000",
"fee_rate_milli_msat": "1",
"disabled": false,
"max_htlc_msat": "9900000000",
"last_update": 1733192887,
"custom_records": {},
"inbound_fee_base_msat": 0,
"inbound_fee_rate_milli_msat": 0
},
"node2_policy": {
"time_lock_delta": 80,
"min_htlc": "1000",
"fee_base_msat": "1000",
"fee_rate_milli_msat": "10",
"disabled": false,
"max_htlc_msat": "9900000000",
"last_update": 1733192887,
"custom_records": {},
"inbound_fee_base_msat": 0,
"inbound_fee_rate_milli_msat": 0
},
"custom_records": {}
}
$ lncli --lnddir=knowledge/lnd_alice -n regtest --rpcserver=127.0.0.1:10010 sendpayment --pay_req="lnbcrt1pn5ulwxpp5hleus2vrjx29ercwtxuzgyrpl8ckkexmprlm9eps0nrl4jn30mpsdqqcqzzsxqyz5vqsp55zavqw9rv5xfxnw6vucluqfrspazwfz7hl4hsqhagnhvrkywyuls9p4gqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqpqysgqlm77eh73g68dkxy4pjf4stjc3tg6yxf9z6ua5l0axjn4tznw2lpsjcdnu8gvug9r095wmg8v56jhmhqzvgz4ch6lmhgrues2hvqe6rspdmdxd5" --amt=5000
Fee hash: bff3c8298391945c8f0e59b8241061f9f16b64db08ffb2e4307cc7faca717ec3
Description:
Quantity (in satoshis): 5000
Price restrict (in satoshis): 250
Vacation spot: 030fb4423c15e3e049dbbdc646d0ef3ab7450a891652bbe0c39a14a8f5b44dc15f
Affirm fee (sure/no): sure
+------------+--------------+--------------+--------------+-----+----------+-----------------+----------------------+
| HTLC_STATE | ATTEMPT_TIME | RESOLVE_TIME | RECEIVER_AMT | FEE | TIMELOCK | CHAN_OUT | ROUTE |
+------------+--------------+--------------+--------------+-----+----------+-----------------+----------------------+
| SUCCEEDED | 0.016 | 0.152 | 5000 | 0 | 555 | 513471930236928 | 030fb4423c15e3e049db |
+------------+--------------+--------------+--------------+-----+----------+-----------------+----------------------+
Quantity + charge: 5000 + 0 sat
Fee hash: bff3c8298391945c8f0e59b8241061f9f16b64db08ffb2e4307cc7faca717ec3
Fee standing: SUCCEEDED, preimage: 47f028b0b825f07e8325735c3e84541e7f5e982635136cee32dff590a21465eb
$ lncli --lnddir=knowledge/lnd_alice -n regtest --rpcserver=127.0.0.1:10010 channelbalance
{
"steadiness": "9956530",
"pending_open_balance": "0",
"local_balance": {
"sat": "9956530",
"msat": "9956530000"
},
"remote_balance": {
"sat": "40000",
"msat": "40000000"
},
"unsettled_local_balance": {
"sat": "0",
"msat": "0"
},
"unsettled_remote_balance": {
"sat": "0",
"msat": "0"
},
"pending_open_local_balance": {
"sat": "0",
"msat": "0"
},
"pending_open_remote_balance": {
"sat": "0",
"msat": "0"
}
}
$ lncli --lnddir=knowledge/lnd_alice -n regtest --rpcserver=127.0.0.1:10010 feereport
{
"channel_fees": [
{
"chan_id": "513471930236928",
"channel_point": "df79c5246a3f1f8dfd6c983106b743a8220a1f4c819b76aeb41d69ccfc2baf4e:0",
"base_fee_msat": "1000",
"fee_per_mil": "10",
"fee_rate": 0.00001,
"inbound_base_fee_msat": 0,
"inbound_fee_per_mil": 0
}
],
"day_fee_sum": "0",
"week_fee_sum": "0",
"month_fee_sum": "0"
}
Bob is simply making an attempt to pay a few of that BTC again to Alice utilizing the identical Lightning channel that Alice opened and funded:
$ lncli --lnddir=knowledge/lnd_bob -n regtest --rpcserver=127.0.0.1:10009 sendpayment --pay_req="lnbcrt1pn5u778pp5xe7ey4lxnevntdveqaaxwtjw29j3yqqtrqqgdxqxylckjndsd56qdqqcqzzsxqyz5vqsp574v9pxu5lja7mjn9uv95uu3mep64w7w00gsedjsse94h2t0xq2zq9p4gqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqpqysgqs0z2xmy9a0un69k8xpp7x2nl8z5ryn25n8n8fet78adax327ksvyll4wdk6s2h58yg8gw8mdqre288uc3edagpg8ave4l8rnxz3kz7sqxj2dhu" --amt=2000
Fee hash: 367d9257e69e5935b599077a672e4e516512000b180086980627f1694db06d34
Description:
Quantity (in satoshis): 2000
Price restrict (in satoshis): 100
Vacation spot: 03f23e9d775b5363a2311742209fc4d50eb47e8c226b78472609356f9d72294729
Affirm fee (sure/no): sure
+------------+--------------+--------------+--------------+-----+----------+----------+-------+
| HTLC_STATE | ATTEMPT_TIME | RESOLVE_TIME | RECEIVER_AMT | FEE | TIMELOCK | CHAN_OUT | ROUTE |
+------------+--------------+--------------+--------------+-----+----------+----------+-------+
+------------+--------------+--------------+--------------+-----+----------+----------+-------+
Quantity + charge: 0 + 0 sat
Fee hash: 367d9257e69e5935b599077a672e4e516512000b180086980627f1694db06d34
Fee standing: FAILED, purpose: FAILURE_REASON_INSUFFICIENT_BALANCE
[lncli] FAILED
$ lncli --lnddir=lnd_bob -n regtest --rpcserver=127.0.0.1:10010 channelbalance
{
"steadiness": "40000",
"pending_open_balance": "0",
"local_balance": {
"sat": "40000",
"msat": "40000000"
},
"remote_balance": {
"sat": "9956530",
"msat": "9956530000"
},
"unsettled_local_balance": {
"sat": "0",
"msat": "0"
},
"unsettled_remote_balance": {
"sat": "0",
"msat": "0"
},
"pending_open_local_balance": {
"sat": "0",
"msat": "0"
},
"pending_open_remote_balance": {
"sat": "0",
"msat": "0"
}
}
$ lncli --lnddir=lnd_bob -n regtest --rpcserver=127.0.0.1:10010 listpeers
{
"friends": [
{
"pub_key": "03f23e9d775b5363a2311742209fc4d50eb47e8c226b78472609356f9d72294729",
"address": "127.0.0.1:60194",
"bytes_sent": "92017",
"bytes_recv": "82927",
"sat_sent": "0",
"sat_recv": "5000",
"inbound": true,
"ping_time": "974",
"sync_type": "ACTIVE_SYNC",
"features": {
"0": {
"name": "data-loss-protect",
"is_required": true,
"is_known": true
},
"5": {
"name": "upfront-shutdown-script",
"is_required": false,
"is_known": true
},
"7": {
"name": "gossip-queries",
"is_required": false,
"is_known": true
},
"8": {
"name": "tlv-onion",
"is_required": true,
"is_known": true
},
"12": {
"name": "static-remote-key",
"is_required": true,
"is_known": true
},
"14": {
"name": "payment-addr",
"is_required": true,
"is_known": true
},
"17": {
"name": "multi-path-payments",
"is_required": false,
"is_known": true
},
"23": {
"name": "anchors-zero-fee-htlc-tx",
"is_required": false,
"is_known": true
},
"25": {
"name": "route-blinding",
"is_required": false,
"is_known": true
},
"27": {
"name": "shutdown-any-segwit",
"is_required": false,
"is_known": true
},
"31": {
"name": "amp",
"is_required": false,
"is_known": true
},
"45": {
"name": "explicit-commitment-type",
"is_required": false,
"is_known": true
},
"2023": {
"name": "script-enforced-lease",
"is_required": false,
"is_known": true
}
},
"errors": [],
"flap_count": 7,
"last_flap_ns": "1733192845755233591",
"last_ping_payload": "00000020d22b2aa43b49ef1fd79d668a09a6562f0e40ffe75eeda662d978cb3d5454290af3b209f13de7fec7f63fc2f4c361db7bb10606af6622289890316905c5da663db6884e67ffff7f2001000000"
}
]
}
$ lncli --lnddir=lnd_bob -n regtest --rpcserver=127.0.0.1:10010 queryroutes --dest 03f23e9d775b5363a2311742209fc4d50eb47e8c226b78472609356f9d72294729 --amt 2000
[lncli] rpc error: code = Unknown desc = inadequate native steadiness
The one means for Bob to ship funds again to Alice appears to be for Bob to open his personal separate channel and ship the fee via that (i.e. outbound liquidity). I don’t perceive why inbound liquidity on Alice’s channel is not working.
Feedback, recommendations, additional questions can be appreciated!
