diff --git a/.env.mainnet b/.env.mainnet
index ac9e52b66..984302812 100644
--- a/.env.mainnet
+++ b/.env.mainnet
@@ -23,6 +23,12 @@ BASE_NODE_L2_ENGINE_RPC=ws://execution:8551
 BASE_NODE_L2_ENGINE_AUTH=/tmp/engine-auth-jwt
 BASE_NODE_L2_ENGINE_AUTH_RAW=688f5d737bad920bdfb2fc2f488d6b6209eebda1dae949a8de91398d932c517a
 
+# RPC CONFIGURATION
+# -----------------
+# Must match the container-side port in the docker-compose.yml port mapping (7545:8545).
+# base-consensus defaults to 9545 if unset, which breaks the existing port mapping.
+BASE_NODE_RPC_PORT=8545
+
 # P2P CONFIGURATION
 # -----------------
 BASE_NODE_P2P_LISTEN_IP=0.0.0.0
diff --git a/.env.sepolia b/.env.sepolia
index e518129fb..4a2c3d379 100644
--- a/.env.sepolia
+++ b/.env.sepolia
@@ -23,6 +23,12 @@ BASE_NODE_L2_ENGINE_RPC=http://execution:8551
 BASE_NODE_L2_ENGINE_AUTH=/tmp/engine-auth-jwt
 BASE_NODE_L2_ENGINE_AUTH_RAW=688f5d737bad920bdfb2fc2f488d6b6209eebda1dae949a8de91398d932c517a
 
+# RPC CONFIGURATION
+# -----------------
+# Must match the container-side port in the docker-compose.yml port mapping (7545:8545).
+# base-consensus defaults to 9545 if unset, which breaks the existing port mapping.
+BASE_NODE_RPC_PORT=8545
+
 # P2P CONFIGURATION
 # -----------------
 BASE_NODE_P2P_LISTEN_IP=0.0.0.0
diff --git a/README.md b/README.md
index 2e0b62998..b23974b3d 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,7 @@ The following are the hardware specifications we use in production:
 - `BASE_NODE_L1_BEACON`: your L1 beacon node endpoint
 - `BASE_NODE_NETWORK`: `base` or `base-sepolia`
 - `RETH_CHAIN`: `base` or `base-sepolia`
+- `BASE_NODE_RPC_PORT`: consensus RPC listen port — must be `8545` to match the `docker-compose.yml` port mapping (`7545:8545`); defaults to `9545` if unset, which makes the consensus RPC unreachable from the host
 
 ### Network Settings