Relaying of Handshake Messages

This section describes the configuration and commands that can be used to start Hermes and relay both handshake and packets for connections and channels.

The start Command

To relay packets and handshake messages configure the mode section of the configuration file like so:

[global]
log_level = 'info'

[mode]

[mode.clients]
enabled = true
# ...

[mode.connections]
enabled = true

[mode.channels]
enabled = true

[mode.packets]
enabled = true
# ...

Then start Hermes using the start command:

hermes start

Hermes sends handshake and packet transactions triggered by IBC events.

Completing Channel Handshakes

After Hermes is started using the start command, it scans the chain state and will resume the handshake for any channels or connections that are not in open state. It then listens to IBC events emitted by any of the configured chains.

Assuming the events are coming from a source chain, Hermes determines the destination chain and builds the handshake messages based on these events. These are then sent to the destination chain.

In addition to the events described in Packet Relaying, the following IBC events may be handled:

  • Channels (if mode.channels.enabled=true):

    • chan_open_init: Hermes builds a MsgChannelOpenTry message
    • chan_open_try: Hermes builds a MsgChannelOpenAck message
    • chan_open_ack: Hermes builds a MsgChannelOpenConfirm message
    • chan_open_confirm: no message is sent out, channel opening is finished

  • Connections (if mode.connections.enabled=true):

    • conn_open_init: Hermes builds a MsgConnOpenTry message
    • conn_open_try: Hermes builds a MsgConnOpenAck message
    • conn_open_ack: Hermes builds a MsgConnOpenConfirm message
    • conn_open_confirm: no message is sent out, connection opening is finished