diff --git a/Cargo.lock b/Cargo.lock
index c3fede4..d708597 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -805,6 +805,7 @@ dependencies = [
  "tonic",
  "tonic-build",
  "tower 0.5.1",
+ "url-builder",
  "uuid",
  "vmm",
 ]
@@ -3566,6 +3567,12 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "url-builder"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c560d19163937c53680c515b82a9311c5a796691c67890b8ad579423123e194"
+
 [[package]]
 name = "utf16_iter"
 version = "1.0.5"
diff --git a/Cargo.toml b/Cargo.toml
index f9229ff..9dff270 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -55,6 +55,7 @@ libc = "0.2"
 pelite = "0.10"
 regex = "1.10"
 structopt = "0.3.26"
+url-builder = "0.1.1"
 
 [build-dependencies]
 tonic-build = "0.12.3"
diff --git a/src/bin/feos_cli/client.rs b/src/bin/feos_cli/client.rs
index cec4031..bc542ce 100644
--- a/src/bin/feos_cli/client.rs
+++ b/src/bin/feos_cli/client.rs
@@ -19,7 +19,7 @@ pub mod feos_grpc {
 #[structopt(name = "feos-cli")]
 pub struct Opt {
     #[structopt(short, long, default_value = "::1")]
-    pub server_ip: String,
+    pub server: String,
     #[structopt(short, long, default_value = "1337")]
     pub port: u16,
     #[structopt(subcommand)]
@@ -67,18 +67,12 @@ pub enum Command {
     IsolatedContainer(IsolatedContainerCommand),
 }
 
-fn format_address(ip: &str, port: u16) -> String {
-    if ip.contains(':') {
-        // IPv6 address
-        format!("http://[{}]:{}", ip, port)
-    } else {
-        // IPv4 address
-        format!("http://{}:{}", ip, port)
-    }
-}
-
 pub async fn run_client(opt: Opt) -> Result<(), Box<dyn std::error::Error>> {
-    let address = format_address(&opt.server_ip, opt.port);
+    let mut ub = URLBuilder::new();
+    ub.set_protocol("http")
+        .set_host(server.as_str())
+        .set_port(port);
+    let address = ub.build();
     let endpoint = Endpoint::from_shared(address)?
         .keep_alive_while_idle(true)
         .keep_alive_timeout(Duration::from_secs(20));
@@ -88,12 +82,12 @@ pub async fn run_client(opt: Opt) -> Result<(), Box<dyn std::error::Error>> {
 
     match opt.cmd {
         Command::Container(container_cmd) => {
-            crate::client_container::run_container_client(opt.server_ip, opt.port, container_cmd)
+            crate::client_container::run_container_client(opt.server, opt.port, container_cmd)
                 .await?;
         }
         Command::IsolatedContainer(container_cmd) => {
             crate::client_isolated_container::run_isolated_container_client(
-                opt.server_ip,
+                opt.server,
                 opt.port,
                 container_cmd,
             )
diff --git a/src/bin/feos_cli/client_container.rs b/src/bin/feos_cli/client_container.rs
index 970667f..49f21ae 100644
--- a/src/bin/feos_cli/client_container.rs
+++ b/src/bin/feos_cli/client_container.rs
@@ -6,6 +6,7 @@ use tonic::Request;
 
 use container_grpc::container_service_client::ContainerServiceClient;
 use container_grpc::*;
+use url_builder::URLBuilder;
 
 pub mod container_grpc {
     tonic::include_proto!("container");
@@ -33,11 +34,15 @@ pub enum ContainerCommand {
 }
 
 pub async fn run_container_client(
-    server_ip: String,
+    server: String,
     port: u16,
     cmd: ContainerCommand,
 ) -> Result<(), Box<dyn std::error::Error>> {
-    let address = format!("http://{}:{}", server_ip, port);
+    let mut ub = URLBuilder::new();
+    ub.set_protocol("http")
+        .set_host(server.as_str())
+        .set_port(port);
+    let address = ub.build();
     let channel = Endpoint::from_shared(address)?.connect().await?;
     let mut client = ContainerServiceClient::new(channel);
 
diff --git a/src/bin/feos_cli/client_isolated_container.rs b/src/bin/feos_cli/client_isolated_container.rs
index 5801b98..42ce5a2 100644
--- a/src/bin/feos_cli/client_isolated_container.rs
+++ b/src/bin/feos_cli/client_isolated_container.rs
@@ -6,6 +6,7 @@ use tonic::Request;
 
 use isolated_container_grpc::isolated_container_service_client::IsolatedContainerServiceClient;
 use isolated_container_grpc::*;
+use url_builder::URLBuilder;
 
 pub mod isolated_container_grpc {
     tonic::include_proto!("isolated_container");
@@ -30,11 +31,15 @@ pub enum IsolatedContainerCommand {
 }
 
 pub async fn run_isolated_container_client(
-    server_ip: String,
+    server: String,
     port: u16,
     cmd: IsolatedContainerCommand,
 ) -> Result<(), Box<dyn std::error::Error>> {
-    let address = format!("http://{}:{}", server_ip, port);
+    let mut ub = URLBuilder::new();
+    ub.set_protocol("http")
+        .set_host(server.as_str())
+        .set_port(port);
+    let address = ub.build();
     let channel = Endpoint::from_shared(address)?.connect().await?;
     let mut client = IsolatedContainerServiceClient::new(channel);