diff --git a/src/postgres-util/src/lib.rs b/src/postgres-util/src/lib.rs
index 3835342fdd210..450e91b12ea8f 100644
--- a/src/postgres-util/src/lib.rs
+++ b/src/postgres-util/src/lib.rs
@@ -46,7 +46,10 @@ pub enum PostgresError {
     Ssh(#[source] anyhow::Error),
     /// Error doing io to setup an ssh connection.
     #[error("error communicating with ssh tunnel: {0}")]
-    SshIo(#[from] std::io::Error),
+    SshIo(std::io::Error),
+    /// Error doing io to setup a connection.
+    #[error("IO error in connection: {0}")]
+    Io(#[from] std::io::Error),
     /// A postgres error.
     #[error(transparent)]
     Postgres(#[from] tokio_postgres::Error),
diff --git a/src/postgres-util/src/tunnel.rs b/src/postgres-util/src/tunnel.rs
index 42f1aa81ab51d..d5fca35d7268e 100644
--- a/src/postgres-util/src/tunnel.rs
+++ b/src/postgres-util/src/tunnel.rs
@@ -303,7 +303,9 @@ impl Config {
                 // the singular host in place.
 
                 let privatelink_host = mz_cloud_resources::vpc_endpoint_name(*connection_id);
-                let privatelink_addrs = tokio::net::lookup_host(privatelink_host).await?;
+                // `net::lookup_host` requires a port to be specified, but the port has no effect
+                // on the lookup so use a dummy one
+                let privatelink_addrs = tokio::net::lookup_host((privatelink_host, 11111)).await?;
 
                 // Override the actual IPs to connect to for the TCP connection, leaving the original host in-place
                 // for TLS verification