---
title: "ConnectionOpenTry defines a rpc handler method for MsgConnectionOpenTry."
method: POST
path: "/ibc.core.connection.v1.Msg/ConnectionOpenTry"
tags: ["Msg"]
---

# ConnectionOpenTry defines a rpc handler method for MsgConnectionOpenTry.

`POST /ibc.core.connection.v1.Msg/ConnectionOpenTry`

## Request body

- IbcCoreConnectionV1MsgConnectionOpenTry — MsgConnectionOpenTry defines a msg sent by a Relayer to try to open a connection on Chain B.
  - `client_id` string
  - `client_state` GoogleProtobufAny
    - `@type` string
  - `consensus_height` IbcCoreClientV1Height — Normally the RevisionHeight is incremented at each height while keeping RevisionNumber the same. However some consensus algorithms may choose to reset the height in certain conditions e.g. hard forks, state-machine breaking changes In these cases, the RevisionNumber is incremented so that height continues to be monitonically increasing even as the RevisionHeight gets reset
    - `revision_height` string, uint64
    - `revision_number` string, uint64
  - `counterparty` IbcCoreConnectionV1Counterparty — Counterparty defines the counterparty chain associated with a connection end.
    - `client_id` string — identifies the client on the counterparty chain associated with a given connection.
    - `connection_id` string — identifies the connection end on the counterparty chain associated with a given connection.
    - `prefix` IbcCoreCommitmentV1MerklePrefix
      - `key_prefix` string, byte
  - `counterparty_versions` IbcCoreConnectionV1Version[]
    - `features` string[]
    - `identifier` string
  - `delay_period` string, uint64
  - `host_consensus_state_proof` string, byte
  - `previous_connection_id` string — Deprecated: this field is unused. Crossing hellos are no longer supported in core IBC.
  - `proof_client` string, byte
  - `proof_consensus` string, byte
  - `proof_height` IbcCoreClientV1Height — Normally the RevisionHeight is incremented at each height while keeping RevisionNumber the same. However some consensus algorithms may choose to reset the height in certain conditions e.g. hard forks, state-machine breaking changes In these cases, the RevisionNumber is incremented so that height continues to be monitonically increasing even as the RevisionHeight gets reset
    - `revision_height` string, uint64
    - `revision_number` string, uint64
  - `proof_init` string, byte
  - `signer` string

## Response `200`

A successful response.

- IbcCoreConnectionV1MsgConnectionOpenTryResponse — MsgConnectionOpenTryResponse defines the Msg/ConnectionOpenTry response type.

## Other responses

- `default` — An unexpected error response.

## Changes

- **2024-08-14** `21c607e4fa20` — 1 info
  - api operation id `IbcCoreConnectionV1Msg_ConnectionOpenTry` removed and replaced with `FeeMsg_ConnectionOpenTry`
- **2024-02-23** `54713b4a9d25` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/pokt-network/apis/http-api-console/changes/ibc.core.connection.v1.Msg/ConnectionOpenTry/post.md)

---

[API](https://skmtc.dev/pokt-network/apis/http-api-console.md) · [All operations](https://skmtc.dev/pokt-network/apis/http-api-console/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/pokt-network/http-api-console/revisions/21c607e4fa20/schema)