diff --git a/src/http.rs b/src/http.rs
index b7ddfce..cdbeca2 100644
--- a/src/http.rs
+++ b/src/http.rs
@@ -8,7 +8,7 @@ use crate::{
 use base64::Engine;
 use httparse::Response;
 use smoltcp::wire::IpProtocol;
-use socks5_impl::protocol::{Address, UserKey};
+use socks5_impl::protocol::UserKey;
 use std::{
     cell::RefCell,
     collections::{hash_map::RandomState, HashMap, VecDeque},
@@ -52,7 +52,7 @@ pub struct HttpConnection {
     digest_state: Rc<RefCell<Option<DigestState>>>,
     before: bool,
     credentials: Option<UserKey>,
-    destination: Address,
+    info: ConnectionInfo,
 }
 
 static PROXY_AUTHENTICATE: &str = "Proxy-Authenticate";
@@ -80,7 +80,7 @@ impl HttpConnection {
             digest_state,
             before: false,
             credentials,
-            destination: info.dst.clone(),
+            info: info.clone(),
         };
 
         res.send_tunnel_request()?;
@@ -89,9 +89,9 @@ impl HttpConnection {
 
     fn send_tunnel_request(&mut self) -> Result<(), Error> {
         self.server_outbuf.extend(b"CONNECT ");
-        self.server_outbuf.extend(self.destination.to_string().as_bytes());
+        self.server_outbuf.extend(self.info.dst.to_string().as_bytes());
         self.server_outbuf.extend(b" HTTP/1.1\r\nHost: ");
-        self.server_outbuf.extend(self.destination.to_string().as_bytes());
+        self.server_outbuf.extend(self.info.dst.to_string().as_bytes());
         self.server_outbuf.extend(b"\r\n");
 
         self.send_auth_data(if self.digest_state.borrow().is_none() {
@@ -111,7 +111,7 @@ impl HttpConnection {
 
         match scheme {
             AuthenticationScheme::Digest => {
-                let uri = self.destination.to_string();
+                let uri = self.info.dst.to_string();
 
                 let context = digest_auth::AuthContext::new_with_method(
                     &credentials.username,
@@ -318,6 +318,10 @@ impl HttpConnection {
 }
 
 impl TcpProxy for HttpConnection {
+    fn get_connection_info(&self) -> &ConnectionInfo {
+        &self.info
+    }
+
     fn push_data(&mut self, event: IncomingDataEvent<'_>) -> Result<(), Error> {
         let direction = event.direction;
         let buffer = event.buffer;
@@ -378,6 +382,10 @@ impl TcpProxy for HttpConnection {
     fn reset_connection(&self) -> bool {
         self.state == HttpState::Reset
     }
+
+    fn get_udp_associate(&self) -> Option<SocketAddr> {
+        None
+    }
 }
 
 pub(crate) struct HttpManager {
@@ -387,11 +395,7 @@ pub(crate) struct HttpManager {
 }
 
 impl ConnectionManager for HttpManager {
-    fn handles_connection(&self, info: &ConnectionInfo) -> bool {
-        info.protocol == IpProtocol::Tcp
-    }
-
-    fn new_tcp_proxy(&self, info: &ConnectionInfo) -> Result<Box<dyn TcpProxy>, Error> {
+    fn new_tcp_proxy(&self, info: &ConnectionInfo, _: bool) -> Result<Box<dyn TcpProxy>, Error> {
         if info.protocol != IpProtocol::Tcp {
             return Err("Invalid protocol".into());
         }
diff --git a/src/lib.rs b/src/lib.rs
index 01ea7ba..bdbf7a0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -130,7 +130,7 @@ pub fn tun_to_proxy<'a>(
         ProxyType::Socks5 => Rc::new(SocksProxyManager::new(server, Version::V5, credentials)) as Rc<dyn ConnectionManager>,
         ProxyType::Http => Rc::new(HttpManager::new(server, credentials)) as Rc<dyn ConnectionManager>,
     };
-    ttp.add_connection_manager(mgr);
+    ttp.set_connection_manager(Some(mgr));
     Ok(ttp)
 }
 
diff --git a/src/socks.rs b/src/socks.rs
index ec4bf39..3e4a7a9 100644
--- a/src/socks.rs
+++ b/src/socks.rs
@@ -1,13 +1,12 @@
 use crate::{
-    error::Error,
+    error::{Error, Result},
     tun2proxy::{
         ConnectionInfo, ConnectionManager, Direction, IncomingDataEvent, IncomingDirection, OutgoingDataEvent,
         OutgoingDirection, TcpProxy,
     },
 };
-use smoltcp::wire::IpProtocol;
 use socks5_impl::protocol::{self, handshake, password_method, Address, AuthMethod, StreamOperation, UserKey, Version};
-use std::{collections::VecDeque, net::SocketAddr};
+use std::{collections::VecDeque, convert::TryFrom, net::SocketAddr};
 
 #[derive(Eq, PartialEq, Debug)]
 #[allow(dead_code)]
@@ -31,10 +30,17 @@ struct SocksProxyImpl {
     data_buf: VecDeque<u8>,
     version: Version,
     credentials: Option<UserKey>,
+    command: protocol::Command,
+    udp_associate: Option<SocketAddr>,
 }
 
 impl SocksProxyImpl {
-    fn new(info: &ConnectionInfo, credentials: Option<UserKey>, version: Version) -> Result<Self, Error> {
+    fn new(
+        info: &ConnectionInfo,
+        credentials: Option<UserKey>,
+        version: Version,
+        command: protocol::Command,
+    ) -> Result<Self> {
         let mut result = Self {
             info: info.clone(),
             state: SocksState::ServerHello,
@@ -45,6 +51,8 @@ impl SocksProxyImpl {
             data_buf: VecDeque::default(),
             version,
             credentials,
+            command,
+            udp_associate: None,
         };
         result.send_client_hello()?;
         Ok(result)
@@ -150,11 +158,11 @@ impl SocksProxyImpl {
             return Err("SOCKS5 server requires an unsupported authentication method.".into());
         }
 
-        if auth_method == AuthMethod::UserPass {
-            self.state = SocksState::SendAuthData;
+        self.state = if auth_method == AuthMethod::UserPass {
+            SocksState::SendAuthData
         } else {
-            self.state = SocksState::SendRequest;
-        }
+            SocksState::SendRequest
+        };
         self.state_change()
     }
 
@@ -195,8 +203,7 @@ impl SocksProxyImpl {
     }
 
     fn send_request_socks5(&mut self) -> Result<(), Error> {
-        protocol::Request::new(protocol::Command::Connect, self.info.dst.clone())
-            .write_to_stream(&mut self.server_outbuf)?;
+        protocol::Request::new(self.command, self.info.dst.clone()).write_to_stream(&mut self.server_outbuf)?;
         self.state = SocksState::ReceiveResponse;
         self.state_change()
     }
@@ -216,6 +223,11 @@ impl SocksProxyImpl {
         if response.reply != protocol::Reply::Succeeded {
             return Err(format!("SOCKS connection failed: {}", response.reply).into());
         }
+        if self.command == protocol::Command::UdpAssociate {
+            self.udp_associate = Some(SocketAddr::try_from(&response.address)?);
+            assert!(self.data_buf.is_empty());
+            log::debug!("UDP associate: {}", response.address);
+        }
 
         self.server_outbuf.append(&mut self.data_buf);
         self.data_buf.clear();
@@ -252,6 +264,10 @@ impl SocksProxyImpl {
 }
 
 impl TcpProxy for SocksProxyImpl {
+    fn get_connection_info(&self) -> &ConnectionInfo {
+        &self.info
+    }
+
     fn push_data(&mut self, event: IncomingDataEvent<'_>) -> Result<(), Error> {
         let direction = event.direction;
         let buffer = event.buffer;
@@ -312,6 +328,10 @@ impl TcpProxy for SocksProxyImpl {
     fn reset_connection(&self) -> bool {
         false
     }
+
+    fn get_udp_associate(&self) -> Option<SocketAddr> {
+        self.udp_associate
+    }
 }
 
 pub(crate) struct SocksProxyManager {
@@ -321,19 +341,11 @@ pub(crate) struct SocksProxyManager {
 }
 
 impl ConnectionManager for SocksProxyManager {
-    fn handles_connection(&self, info: &ConnectionInfo) -> bool {
-        info.protocol == IpProtocol::Tcp
-    }
-
-    fn new_tcp_proxy(&self, info: &ConnectionInfo) -> Result<Box<dyn TcpProxy>, Error> {
-        if info.protocol != IpProtocol::Tcp {
-            return Err("Invalid protocol".into());
-        }
-        Ok(Box::new(SocksProxyImpl::new(
-            info,
-            self.credentials.clone(),
-            self.version,
-        )?))
+    fn new_tcp_proxy(&self, info: &ConnectionInfo, udp_associate: bool) -> Result<Box<dyn TcpProxy>> {
+        use socks5_impl::protocol::Command::{Connect, UdpAssociate};
+        let command = if udp_associate { UdpAssociate } else { Connect };
+        let credentials = self.credentials.clone();
+        Ok(Box::new(SocksProxyImpl::new(info, credentials, self.version, command)?))
     }
 
     fn close_connection(&self, _: &ConnectionInfo) {}
diff --git a/src/tun2proxy.rs b/src/tun2proxy.rs
index e33f43b..ea1078d 100644
--- a/src/tun2proxy.rs
+++ b/src/tun2proxy.rs
@@ -7,7 +7,7 @@ use smoltcp::{
     time::Instant,
     wire::{IpCidr, IpProtocol, Ipv4Packet, Ipv6Packet, TcpPacket, UdpPacket, UDP_HEADER_LEN},
 };
-use socks5_impl::protocol::{Address, UserKey};
+use socks5_impl::protocol::{Address, StreamOperation, UdpHeader, UserKey};
 use std::{
     collections::{HashMap, HashSet},
     convert::{From, TryFrom},
@@ -18,7 +18,7 @@ use std::{
     str::FromStr,
 };
 
-#[derive(Hash, Clone, Eq, PartialEq, Debug)]
+#[derive(Hash, Clone, Eq, PartialEq, PartialOrd, Ord, Debug)]
 pub(crate) struct ConnectionInfo {
     pub(crate) src: SocketAddr,
     pub(crate) dst: Address,
@@ -36,7 +36,6 @@ impl Default for ConnectionInfo {
 }
 
 impl ConnectionInfo {
-    #[allow(dead_code)]
     pub fn new(src: SocketAddr, dst: Address, protocol: IpProtocol) -> Self {
         Self { src, dst, protocol }
     }
@@ -133,11 +132,11 @@ fn connection_tuple(frame: &[u8]) -> Result<(ConnectionInfo, bool, usize, usize)
 
         let (ports, first_packet, payload_offset, payload_size) =
             get_transport_info(protocol, header_len, &frame[header_len..])?;
-        let info = ConnectionInfo {
-            src: SocketAddr::new(src_addr, ports.0),
-            dst: SocketAddr::new(dst_addr, ports.1).into(),
+        let info = ConnectionInfo::new(
+            SocketAddr::new(src_addr, ports.0),
+            SocketAddr::new(dst_addr, ports.1).into(),
             protocol,
-        };
+        );
         return Ok((info, first_packet, payload_offset, payload_size));
     }
 
@@ -154,11 +153,11 @@ fn connection_tuple(frame: &[u8]) -> Result<(ConnectionInfo, bool, usize, usize)
 
         let (ports, first_packet, payload_offset, payload_size) =
             get_transport_info(protocol, header_len, &frame[header_len..])?;
-        let info = ConnectionInfo {
-            src: SocketAddr::new(src_addr, ports.0),
-            dst: SocketAddr::new(dst_addr, ports.1).into(),
+        let info = ConnectionInfo::new(
+            SocketAddr::new(src_addr, ports.0),
+            SocketAddr::new(dst_addr, ports.1).into(),
             protocol,
-        };
+        );
         return Ok((info, first_packet, payload_offset, payload_size));
     }
     Err("Neither IPv6 nor IPv4 packet".into())
@@ -178,12 +177,14 @@ struct TcpConnectState {
 }
 
 pub(crate) trait TcpProxy {
+    fn get_connection_info(&self) -> &ConnectionInfo;
     fn push_data(&mut self, event: IncomingDataEvent<'_>) -> Result<(), Error>;
     fn consume_data(&mut self, dir: OutgoingDirection, size: usize);
     fn peek_data(&mut self, dir: OutgoingDirection) -> OutgoingDataEvent;
     fn connection_established(&self) -> bool;
     fn have_data(&mut self, dir: Direction) -> bool;
     fn reset_connection(&self) -> bool;
+    fn get_udp_associate(&self) -> Option<SocketAddr>;
 }
 
 pub(crate) trait UdpProxy {
@@ -192,8 +193,7 @@ pub(crate) trait UdpProxy {
 }
 
 pub(crate) trait ConnectionManager {
-    fn handles_connection(&self, info: &ConnectionInfo) -> bool;
-    fn new_tcp_proxy(&self, info: &ConnectionInfo) -> Result<Box<dyn TcpProxy>, Error>;
+    fn new_tcp_proxy(&self, info: &ConnectionInfo, udp_associate: bool) -> Result<Box<dyn TcpProxy>>;
     fn close_connection(&self, info: &ConnectionInfo);
     fn get_server_addr(&self) -> SocketAddr;
     fn get_credentials(&self) -> &Option<UserKey>;
@@ -207,9 +207,8 @@ pub struct TunToProxy<'a> {
     poll: Poll,
     iface: Interface,
     connection_map: HashMap<ConnectionInfo, TcpConnectState>,
-    connection_managers: Vec<Rc<dyn ConnectionManager>>,
+    connection_manager: Option<Rc<dyn ConnectionManager>>,
     next_token: usize,
-    token_to_info: HashMap<Token, ConnectionInfo>,
     sockets: SocketSet<'a>,
     device: VirtualTunDevice,
     options: Options,
@@ -256,8 +255,7 @@ impl<'a> TunToProxy<'a> {
             iface,
             connection_map: HashMap::default(),
             next_token: usize::from(EXIT_TOKEN) + 1,
-            token_to_info: HashMap::default(),
-            connection_managers: Vec::default(),
+            connection_manager: None,
             sockets: SocketSet::new([]),
             device,
             options,
@@ -274,8 +272,8 @@ impl<'a> TunToProxy<'a> {
         token
     }
 
-    pub(crate) fn add_connection_manager(&mut self, manager: Rc<dyn ConnectionManager>) {
-        self.connection_managers.push(manager);
+    pub(crate) fn set_connection_manager(&mut self, manager: Option<Rc<dyn ConnectionManager>>) {
+        self.connection_manager = manager;
     }
 
     /// Read data from virtual device (remote server) and inject it into tun interface.
@@ -296,36 +294,41 @@ impl<'a> TunToProxy<'a> {
         Ok(())
     }
 
+    fn find_info_by_token(&self, token: Token) -> Option<&ConnectionInfo> {
+        self.connection_map
+            .iter()
+            .find_map(|(info, state)| if state.token == token { Some(info) } else { None })
+    }
+
+    /// Destroy connection state machine
     fn remove_connection(&mut self, info: &ConnectionInfo) -> Result<(), Error> {
-        if let Some(mut conn) = self.connection_map.remove(info) {
-            _ = conn.mio_stream.shutdown(Shutdown::Both);
-            if let Some(handle) = conn.smoltcp_handle {
+        if let Some(mut state) = self.connection_map.remove(info) {
+            _ = state.mio_stream.shutdown(Shutdown::Both);
+            if let Some(handle) = state.smoltcp_handle {
                 let socket = self.sockets.get_mut::<tcp::Socket>(handle);
                 socket.close();
                 self.sockets.remove(handle);
             }
+
+            // FIXME: Does this line should be moved up to the beginning of this function?
             self.expect_smoltcp_send()?;
-            let token = &conn.token;
-            self.token_to_info.remove(token);
-            _ = self.poll.registry().deregister(&mut conn.mio_stream);
+
+            _ = self.poll.registry().deregister(&mut state.mio_stream);
+
             log::info!("Close {}", info);
         }
         Ok(())
     }
 
-    fn get_connection_manager(&self, info: &ConnectionInfo) -> Option<Rc<dyn ConnectionManager>> {
-        for manager in self.connection_managers.iter() {
-            if manager.handles_connection(info) {
-                return Some(manager.clone());
-            }
-        }
-        None
+    fn get_connection_manager(&self) -> Option<Rc<dyn ConnectionManager>> {
+        self.connection_manager.clone()
     }
 
+    /// Scan connection state machine and check if any connection should be closed.
     fn check_change_close_state(&mut self, info: &ConnectionInfo) -> Result<(), Error> {
         let state = match self.connection_map.get_mut(info) {
-            None => return Ok(()),
             Some(state) => state,
+            None => return Ok(()),
         };
         let mut closed_ends = 0;
         if (state.close_state & SERVER_WRITE_CLOSED) == SERVER_WRITE_CLOSED
@@ -336,8 +339,9 @@ impl<'a> TunToProxy<'a> {
                 .tcp_proxy_handler
                 .have_data(Direction::Outgoing(OutgoingDirection::ToClient))
         {
-            if let Some(socket_handle) = state.smoltcp_handle {
-                let socket = self.sockets.get_mut::<tcp::Socket>(socket_handle);
+            if let Some(handle) = state.smoltcp_handle {
+                // Close tun interface
+                let socket = self.sockets.get_mut::<tcp::Socket>(handle);
                 socket.close();
             }
             closed_ends += 1;
@@ -351,17 +355,20 @@ impl<'a> TunToProxy<'a> {
                 .tcp_proxy_handler
                 .have_data(Direction::Outgoing(OutgoingDirection::ToServer))
         {
+            // Close remote server
             _ = state.mio_stream.shutdown(Shutdown::Write);
             closed_ends += 1;
         }
 
         if closed_ends == 2 {
+            // Close connection state machine
             self.remove_connection(info)?;
         }
         Ok(())
     }
 
     fn tunsocket_read_and_forward(&mut self, info: &ConnectionInfo) -> Result<(), Error> {
+        // 1. Read data from tun and write to proxy handler (remote server).
         // Scope for mutable borrow of self.
         {
             let state = match self.connection_map.get_mut(info) {
@@ -393,10 +400,10 @@ impl<'a> TunToProxy<'a> {
                 // need to send data.
                 state.close_state |= CLIENT_WRITE_CLOSED;
             }
-
-            // Expect ACKs etc. from smoltcp sockets.
-            self.expect_smoltcp_send()?;
         }
+        // 2. Write data from proxy handler (remote server) to tun.
+        // Expect ACKs etc. from smoltcp sockets.
+        self.expect_smoltcp_send()?;
 
         self.check_change_close_state(info)?;
 
@@ -426,7 +433,12 @@ impl<'a> TunToProxy<'a> {
     // A raw packet was received on the tunnel interface.
     fn receive_tun(&mut self, frame: &mut [u8]) -> Result<(), Error> {
         let mut handler = || -> Result<(), Error> {
-            let (info, first_packet, payload_offset, payload_size) = connection_tuple(frame)?;
+            let result = connection_tuple(frame);
+            if let Err(error) = result {
+                log::info!("{}, ignored", error);
+                return Ok(());
+            }
+            let (info, _first_packet, payload_offset, payload_size) = result?;
             let dst = SocketAddr::try_from(&info.dst)?;
             let connection_info = match &mut self.options.virtual_dns {
                 None => info.clone(),
@@ -439,33 +451,17 @@ impl<'a> TunToProxy<'a> {
                     }
                 }
             };
+
+            let manager = self.get_connection_manager().ok_or("get connection manager")?;
+            let server_addr = manager.get_server_addr();
+
             if connection_info.protocol == IpProtocol::Tcp {
-                let server_addr = self
-                    .get_connection_manager(&connection_info)
-                    .ok_or("get_connection_manager")?
-                    .get_server_addr();
-                if first_packet {
-                    let mut done = false;
-                    for manager in self.connection_managers.iter_mut() {
-                        let tcp_proxy_handler = manager.new_tcp_proxy(&connection_info);
-                        if tcp_proxy_handler.is_err() {
-                            continue;
-                        }
-                        let tcp_proxy_handler = tcp_proxy_handler?;
-                        self.create_new_tcp_proxy_connection(
-                            server_addr,
-                            dst,
-                            tcp_proxy_handler,
-                            connection_info.clone(),
-                        )?;
-
-                        log::info!("Connect done {} ({})", connection_info, dst);
-                        done = true;
-                        break;
-                    }
-                    if !done {
-                        log::debug!("No connection manager for {} ({})", connection_info, dst);
-                    }
+                if _first_packet {
+                    let tcp_proxy_handler = manager.new_tcp_proxy(&connection_info, false)?;
+                    let state = self.create_new_tcp_connection_state(server_addr, dst, tcp_proxy_handler)?;
+                    self.connection_map.insert(connection_info.clone(), state);
+
+                    log::info!("Connect done {} ({})", connection_info, dst);
                 } else if !self.connection_map.contains_key(&connection_info) {
                     log::debug!("Not found {} ({})", connection_info, dst);
                     return Ok(());
@@ -493,19 +489,33 @@ impl<'a> TunToProxy<'a> {
                 let payload = &frame[payload_offset..payload_offset + payload_size];
                 if let (Some(virtual_dns), true) = (&mut self.options.virtual_dns, port == 53) {
                     let response = virtual_dns.receive_query(payload)?;
-                    {
-                        let rx_buffer = udp::PacketBuffer::new(vec![udp::PacketMetadata::EMPTY], vec![0; 4096]);
-                        let tx_buffer = udp::PacketBuffer::new(vec![udp::PacketMetadata::EMPTY], vec![0; 4096]);
-                        let mut socket = udp::Socket::new(rx_buffer, tx_buffer);
-                        socket.bind(dst)?;
-                        let meta = UdpMetadata::from(connection_info.src);
-                        socket.send_slice(response.as_slice(), meta)?;
-                        let handle = self.sockets.add(socket);
-                        self.expect_smoltcp_send()?;
-                        self.sockets.remove(handle);
+                    self.send_udp_packet(dst, connection_info.src, response.as_slice())?;
+                } else {
+                    // Another UDP packet
+                    if !self.connection_map.contains_key(&connection_info) {
+                        log::trace!("New UDP connection {} ({})", connection_info, dst);
+                        let tcp_proxy_handler = manager.new_tcp_proxy(&connection_info, true)?;
+                        let state = self.create_new_tcp_connection_state(server_addr, dst, tcp_proxy_handler)?;
+                        self.connection_map.insert(connection_info.clone(), state);
+                    }
+
+                    self.expect_smoltcp_send()?;
+                    self.tunsocket_read_and_forward(&connection_info)?;
+                    self.write_to_server(&connection_info)?;
+
+                    let mut s5_udp_data = Vec::<u8>::new();
+                    UdpHeader::new(0, connection_info.dst.clone()).write_to_stream(&mut s5_udp_data)?;
+                    s5_udp_data.extend_from_slice(payload);
+
+                    let state = self.connection_map.get(&connection_info).ok_or("udp associate state")?;
+                    if let Some(udp_associate) = state.tcp_proxy_handler.get_udp_associate() {
+                        log::debug!("UDP associate address: {}", udp_associate);
+                        // Send packets via UDP associate...
+                        // self.send_udp_packet(connection_info.src, udp_associate, &s5_udp_data)?;
+                    } else {
+                        // UDP associate tunnel not ready yet, we must cache the packet...
                     }
                 }
-                // Otherwise, UDP is not yet supported.
             } else {
                 log::warn!("Unsupported protocol: {} ({})", connection_info, dst);
             }
@@ -517,13 +527,12 @@ impl<'a> TunToProxy<'a> {
         Ok(())
     }
 
-    fn create_new_tcp_proxy_connection(
+    fn create_new_tcp_connection_state(
         &mut self,
         server_addr: SocketAddr,
         dst: SocketAddr,
         tcp_proxy_handler: Box<dyn TcpProxy>,
-        connection_info: ConnectionInfo,
-    ) -> Result<()> {
+    ) -> Result<TcpConnectState> {
         let mut socket = tcp::Socket::new(
             tcp::SocketBuffer::new(vec![0; 1024 * 128]),
             tcp::SocketBuffer::new(vec![0; 1024 * 128]),
@@ -546,9 +555,18 @@ impl<'a> TunToProxy<'a> {
             wait_read: true,
             wait_write: false,
         };
-        self.connection_map.insert(connection_info.clone(), state);
+        Ok(state)
+    }
 
-        self.token_to_info.insert(token, connection_info.clone());
+    fn send_udp_packet(&mut self, src: SocketAddr, dst: SocketAddr, data: &[u8]) -> Result<()> {
+        let rx_buffer = udp::PacketBuffer::new(vec![udp::PacketMetadata::EMPTY], vec![0; 4096]);
+        let tx_buffer = udp::PacketBuffer::new(vec![udp::PacketMetadata::EMPTY], vec![0; 4096]);
+        let mut socket = udp::Socket::new(rx_buffer, tx_buffer);
+        socket.bind(src)?;
+        socket.send_slice(data, UdpMetadata::from(dst))?;
+        let handle = self.sockets.add(socket);
+        self.expect_smoltcp_send()?;
+        self.sockets.remove(handle);
         Ok(())
     }
 
@@ -587,7 +605,7 @@ impl<'a> TunToProxy<'a> {
 
     fn write_to_client(&mut self, token: Token, info: &ConnectionInfo) -> Result<(), Error> {
         while let Some(state) = self.connection_map.get_mut(info) {
-            let socket_handle = match state.smoltcp_handle {
+            let handle = match state.smoltcp_handle {
                 Some(handle) => handle,
                 None => break,
             };
@@ -595,7 +613,7 @@ impl<'a> TunToProxy<'a> {
             let buflen = event.buffer.len();
             let consumed;
             {
-                let socket = self.sockets.get_mut::<tcp::Socket>(socket_handle);
+                let socket = self.sockets.get_mut::<tcp::Socket>(handle);
                 if socket.may_send() {
                     if let Some(virtual_dns) = &mut self.options.virtual_dns {
                         // Unwrapping is fine because every smoltcp socket is bound to an.
@@ -635,11 +653,10 @@ impl<'a> TunToProxy<'a> {
     }
 
     fn send_to_smoltcp(&mut self) -> Result<(), Error> {
-        let cloned = self.write_sockets.clone();
-        for token in cloned.iter() {
-            if let Some(connection) = self.token_to_info.get(token) {
+        for token in self.write_sockets.clone().into_iter() {
+            if let Some(connection) = self.find_info_by_token(token) {
                 let connection = connection.clone();
-                if let Err(error) = self.write_to_client(*token, &connection) {
+                if let Err(error) = self.write_to_client(token, &connection) {
                     self.remove_connection(&connection)?;
                     log::error!("Write to client: {}: ", error);
                 }
@@ -649,19 +666,19 @@ impl<'a> TunToProxy<'a> {
     }
 
     fn mio_socket_event(&mut self, event: &Event) -> Result<(), Error> {
-        let e = "connection not found";
-        let conn_info = match self.token_to_info.get(&event.token()) {
+        let conn_info = match self.find_info_by_token(event.token()) {
             Some(conn_info) => conn_info.clone(),
             None => {
                 // We may have closed the connection in an earlier iteration over the poll events,
                 // e.g. because an event through the tunnel interface indicated that the connection
                 // should be closed.
-                log::trace!("{e}");
+                log::trace!("Connection info not found");
                 return Ok(());
             }
         };
 
-        let server = self.get_connection_manager(&conn_info).ok_or(e)?.get_server_addr();
+        let e = "connection manager not found";
+        let server = self.get_connection_manager().ok_or(e)?.get_server_addr();
 
         let mut block = || -> Result<(), Error> {
             if event.is_readable() || event.is_read_closed() {