My lightning node is unreachable and lightning-rpc': Connection refused

Question

I'm trying to use c-lightning on my raspberry. When start the lightning daemon I get two errors: the first one is:

    2020-06-05T17:02:08.784Z DEBUG connectd: Failed to connect 10 socket: Network is unreachable
...
 gossipd: seeker: no peers, waiting

My .lightning/config is:

alias=LIGHTNING_NODE_ROCK
rgb=DDFF06
addr=:9735
log-level=debug
network=testnet
bitcoin-cli=/usr/local/bin/bitcoin-cli
bitcoin-datadir=/home/bitcoin/.bitcoin
log-prefix=raspi-lightning
ignore-fee-limits=true
fee-base=10
bitcoin-rpcuser=user
bitcoin-rpcpassword=userpass
bitcoin-rpcconnect=127.0.0.1
bitcoin-rpcport=18332

my bitcoin.conf is:

testnet=1
[test]
rpcuser=user
rpcpassword=userpass
rpcport=18332
rpcconnect=127.0.0.1

telnet works on my public ip and 9735

I tried to connect to someone like:

bitcoin@raspberrypi:~ $ ln-cli connect 03ad4870c7a9dd0b429958cf9659b1330afbe33df8207cd1c882798cdad1dfb039@5.95.80.47:9737
{
   "code": 401,
   "message": "5.95.80.47:9737: Connection establishment: Connection timed out. "
}

the second problem is:

2020-06-05T17:02:08.864Z UNUSUAL plugin-bcli: Could not connect to 'lightning-rpc': Connection refused
2020-06-05T17:02:08.865Z INFO plugin-bcli: bitcoin-cli initialized and connected to bitcoind.

My Info is:

bitcoin@raspberrypi:/mnt/hdd/bitcoin $ ln-cli getinfo  
{
   "id": "0310e9f97def619a7ee02b321cf2fad4f67b59f2c6bd12456dc8d6d8be125e1b14",
   "alias": "LIGHTNING_NODE_ROCK",
   "color": "ddff06",
   "num_peers": 0,
   "num_pending_channels": 0,
   "num_active_channels": 0,
   "num_inactive_channels": 0,
   "address": [],
   "binding": [
      {
         "type": "ipv6",
         "address": "::",
         "port": 9735
      },
      {
         "type": "ipv4",
         "address": "0.0.0.0",
         "port": 9735
      }
   ],
   "version": "v0.8.2-198-g0f568e1",
   "blockheight": 1747789,
   "network": "testnet",
   "msatoshi_fees_collected": 0,
   "fees_collected_msat": "0msat",
   "lightning-dir": "/home/bitcoin/.lightning/testnet"
}

My testnet is fully sync and I'm able to use rpc calls form my bitcoin-cli

bitcoin@raspberrypi:/mnt/hdd/bitcoin $ bitcoin-cli echo hello world
[
  "hello",
  "world"
]

I don't have any firewall

Answer 1

The first error you are seeing might be related to a previous peer that is no longer reachable. The type of the error (Failed to connect 10 socket: Network is unreachable) suggests that it is using a network that is no longer available. This can be because the peer was connected through Tor, or IPv6, and the Tor proxy isn't running anymore, or the network configuration changed and doesn't support IPv6 anymore. It could also be during OS startup that the network device just isn't ready yet, and this is just transient.

Regarding the connection timeout when attempting to connect to another node, it's likely just not online. I went and checked with nmap if the node is online, and it wasn't when I checked:

Starting Nmap 7.60 ( https://nmap.org ) at 2020-06-06 13:47 CEST
Nmap scan report for net-5-95-80-47.cust.vodafonedsl.it (5.95.80.47)
Host is up.

PORT     STATE    SERVICE
9737/tcp filtered unknown

Nmap done: 1 IP address (1 host up) scanned in 2.05 seconds

So that's nothing out of the ordinary. Might I suggest connecting to some other node?

And finally the UNUSUAL plugin-bcli: Could not connect to 'lightning-rpc': Connection refused error is an artifact from the order in which we start up the plugins and the RPC interface: usually plugins are told that we are ready only after the RPC is made available. The bitcoin-backend plugins are a bit special, because they are needed to check whether we are in sync with the bitcoin network and that we can talk to bitcoind. Therefore the bcli plugin starts before the RPC is ready. The error can be safely ignored and we'll make it less verbose soon (see Github Issue #3553).

Disclaimer: I am one of c-lightning's developers.