diff --git a/Cargo.toml b/Cargo.toml
index f9f5c5b..77b7e28 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,4 +7,4 @@ rust-version = "1.68.2"
 
 [dependencies]
 fqdn = {version = "0.4.2", features = ["domain-label-length-limited-to-63", "domain-name-without-special-chars"]}
-email-address-parser = "2.0.0"
\ No newline at end of file
+email-address-parser = "2.0.0"
diff --git a/src/main.rs b/src/main.rs
index 65eb210..547dbc0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,19 +1,34 @@
 use email_address_parser::EmailAddress;
 use fqdn::FQDN;
-use std::collections::HashMap;
+use std::cmp::Ordering;
+use std::collections::BTreeMap;
 use std::env;
 use std::fs::File;
 use std::io::{self, BufRead};
 use std::path::Path;
 use std::str::FromStr;
 
-#[derive(Debug)]
 struct AliasFile {
     content: io::Lines<io::BufReader<File>>,
     default_domain: FQDN,
 }
 
-type AliasMap = HashMap<EmailAddress, Vec<EmailAddress>>;
+#[derive(PartialEq, Eq, Clone)]
+struct OrdEmailAddress(EmailAddress);
+
+impl PartialOrd for OrdEmailAddress {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.0.to_string().cmp(&other.0.to_string()))
+    }
+}
+
+impl Ord for OrdEmailAddress {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.0.to_string().cmp(&other.0.to_string())
+    }
+}
+
+type AliasMap = BTreeMap<OrdEmailAddress, Vec<OrdEmailAddress>>;
 
 fn main() {
     let args: Vec<String> = env::args().collect();
@@ -35,16 +50,17 @@ fn main() {
 
 fn generate_sieve_script(redirects: AliasMap) -> String {
     let mut script: String = "require [\"envelope\", \"copy\"];\n\n".to_string();
-    for (redirect, destinations) in redirects {
-        script += format!("if envelope :is \"to\" \"{}\" {{\n{}}}\n", redirect, {
+    for (redirect, mut destinations) in redirects {
+        script += format!("if envelope :is \"to\" \"{}\" {{\n{}}}\n", redirect.0, {
             let mut subscript: String = String::new();
+            destinations.sort();
             for destination in destinations.iter().rev().skip(1).rev() {
-                subscript += format!("  redirect :copy \"{destination}\";\n").as_str();
+                subscript += format!("  redirect :copy \"{}\";\n", destination.0).as_str();
             }
             subscript
                 + format!(
                     "  redirect \"{}\";\n",
-                    destinations.iter().next_back().unwrap()
+                    destinations.iter().next_back().unwrap().0
                 )
                 .as_str()
         })
@@ -56,7 +72,7 @@ fn generate_sieve_script(redirects: AliasMap) -> String {
 fn parse_alias_to_map(alias_files: Vec<AliasFile>) -> AliasMap {
     // File must exist in the current path
     let mut redirect_map: AliasMap = AliasMap::new();
-    let mut destinations: Vec<EmailAddress> = Vec::new();
+    let mut destinations: Vec<OrdEmailAddress> = Vec::new();
     for alias_file in alias_files {
         for line in alias_file.content {
             let line = line.unwrap();
@@ -65,7 +81,7 @@ fn parse_alias_to_map(alias_files: Vec<AliasFile>) -> AliasMap {
             if destination.is_empty() {
                 continue;
             }
-            let redirects: Vec<EmailAddress> = line
+            let redirects: Vec<OrdEmailAddress> = line
                 .split_at(line.find(char::is_whitespace).unwrap_or(0))
                 .1
                 .split(' ')
@@ -107,13 +123,13 @@ fn parse_alias_to_map(alias_files: Vec<AliasFile>) -> AliasMap {
     redirect_map
 }
 
-fn to_mailaddress(local_part: &str, default_domain: &FQDN) -> EmailAddress {
+fn to_mailaddress(local_part: &str, default_domain: &FQDN) -> OrdEmailAddress {
     let mut addr = local_part.trim().to_string();
     addr = addr.replace(',', "");
     if addr.contains('@') {
-        return EmailAddress::parse(&addr, None).unwrap();
+        return OrdEmailAddress(EmailAddress::parse(&addr, None).unwrap());
     }
-    EmailAddress::new(&addr, &default_domain.to_string(), None).unwrap()
+    OrdEmailAddress(EmailAddress::new(&addr, &default_domain.to_string(), None).unwrap())
 }
 
 // The output is wrapped in a Result to allow matching on errors.