diff --git a/src/client.rs b/src/client.rs
index 93eb292..6c7a1df 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -25,6 +25,8 @@ use std::{
 
 use crate::{debug, error, info, trace};
 const MAX_THREADS: usize = 50;
+const DEFALT_LISTEN_PORT: u32 = 2234;
+
 pub enum ClientOperation {
     NewPeer(NewPeer),
     ConnectToPeer(Peer),
@@ -69,6 +71,7 @@ impl ClientContext {
     }
 }
 pub struct Client {
+    listen_port: u32,
     address: PeerAddress,
     username: String,
     password: String,
@@ -81,6 +84,7 @@ impl Client {
         address: PeerAddress,
         username: String,
         password: String,
+        listen_port: Option<u32>,
     ) -> Self {
         crate::utils::logger::init();
         let context = Arc::new(RwLock::new(ClientContext::new()));
@@ -89,6 +93,7 @@ impl Client {
             context.read().unwrap().thread_pool.thread_count()
         );
         Self {
+            listen_port: listen_port.unwrap_or(DEFALT_LISTEN_PORT),
             address,
             username,
             password,
@@ -96,6 +101,13 @@ impl Client {
             context,
         }
     }
+    pub fn with_defaults(
+        address: PeerAddress,
+        username: String,
+        password: String,
+    ) -> Self {
+        Self::new(address, username, password, None)
+    }
 
     pub fn connect(&mut self) {
         let (sender, message_reader): (
@@ -103,6 +115,7 @@ impl Client {
             Receiver<ClientOperation>,
         ) = mpsc::channel();
 
+        let listen_port = self.listen_port;
         self.context.write().unwrap().sender = Some(sender.clone());
 
         let client_sender = sender.clone();
@@ -116,7 +129,7 @@ impl Client {
                 );
 
                 thread::spawn(move || {
-                    Listen::start(2234, client_sender.clone());
+                    Listen::start(listen_port, client_sender.clone());
                 });
                 let mut unlocked_context = self.context.write().unwrap();
                 unlocked_context.server_sender =
diff --git a/src/main.rs b/src/main.rs
index b6b4a25..5c744df 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,7 +2,7 @@ fn main() {
     use soulseek_rs::{Client, PeerAddress};
     use std::time::Duration;
 
-    let mut client = Client::new(
+    let mut client = Client::with_defaults(
         // PeerAddress::new(String::from("server.slsknet.org"), 2242),
         PeerAddress::new(String::from("127.0.0.1"), 2242),
         String::from("insane_in_the_brain3"),
diff --git a/src/utils/zlib.rs b/src/utils/zlib.rs
index 599889b..8b52421 100644
--- a/src/utils/zlib.rs
+++ b/src/utils/zlib.rs
@@ -72,7 +72,7 @@ pub fn deflate(input: &[u8]) -> Result<Vec<u8>> {
         return Err(SoulseekRs::CompressionError("invalid CINFO".to_string()));
     }
     let flg = r.read_byte()?;
-    if !((cmf as u32) * 256 + (flg as u32)).is_multiple_of(31) {
+    if ((cmf as u32) * 256 + (flg as u32)) % 31 != 0 {
         return Err(SoulseekRs::CompressionError(
             "CMF+FLG checksum failed".to_string(),
         ));