Unable to open channel to c-lightning node channel reserve vs. dust

[Sjors]

Running SwiftLightning on my iPhone, c-lightning on my Mac (connected to Bitcoin Core on testnet). When trying to open a channel the app complains:

"You have bad parameters:Our channel reserve 546 would be below their dust 573"

cc @cdecker

[cdecker]

This is a failed negotiation of the reserve and dust limits as per spec:

The receiving node MUST fail the channel if:

...

• dust_limit_satoshis is greater than channel_reserve_satoshis.

...

You wouldn't happen to know what the remote endpoint is running? It's using a non-standard dust limit.

[Sjors]

The initiating node (on the phone) is running lnd. The remote node is running c-lightning. I didn't do anything fancy config wise for c-lightning, nor with the core node it uses.

[biscottigelato]

Yeah, my understanding of the dust-limit error message means that after fees, the on-chain transaction have more or less nothing left. In this case nothing left in the channel. Basically the only way to resolve it at this point is to provide more funds into the channel to begin with. In the future if there's a better way to do on-chain fee estimation, the warning can come earlier when the user is still punching in the Funding Amount.