diff --git a/src/icmp.rs b/src/icmp.rs
index be58f03..5e81008 100644
--- a/src/icmp.rs
+++ b/src/icmp.rs
@@ -19,22 +19,22 @@ use std::sync::{Arc, RwLock};
 use std::time::Duration;
 
 gflags::define! {
-    // The size in bytes of the ping requests.
+    /// The size in bytes of the ping requests.
     --pingPayload = "durnitisp"
 }
 
 gflags::define! {
-    // The size in bytes of the ping requests.
+    /// The size in bytes of the ping requests.
     --pingTTL: u32 = 113
 }
 
 gflags::define! {
-    // The size in bytes of the ping requests.
+    /// The size in bytes of the ping requests.
     --pingTimeout: u64 = 2048
 }
 
 gflags::define! {
-    // The size in bytes of the ping requests.
+    /// The size in bytes of the ping requests.
     --maxHops: u8 = 50
 }
 
diff --git a/src/main.rs b/src/main.rs
index f595ecc..89e86a3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -29,12 +29,12 @@ mod stun;
 mod util;
 
 gflags::define! {
-    /// Print this help text.
+    /// Print this help text
     -h, --help = false
 }
 
 gflags::define! {
-    /// Port to listen on for exporting variables prometheus style.
+    /// Port to listen on for exporting variables prometheus style
     --listenHost = "0.0.0.0:8080"
 }
 
@@ -43,6 +43,11 @@ gflags::define! {
     --debug = false
 }
 
+gflags::define! {
+    /// Comma separated list of hosts to ping
+    --pingHosts = "google.com"
+}
+
 fn main() -> anyhow::Result<()> {
     let default_stun_servers: Vec<&'static str> = vec![
         "stun.l.google.com:19302",
@@ -60,8 +65,6 @@ fn main() -> anyhow::Result<()> {
     ];
     let mut stun_servers = gflags::parse();
 
-    let default_ping_hosts: Vec<&'static str> = vec!["google.com"];
-
     if HELP.flag {
         println!("durnitisp <options> <list of hostname:port>");
         println!("");
@@ -87,7 +90,7 @@ fn main() -> anyhow::Result<()> {
         stun_servers = default_stun_servers;
     }
     // FIXME(jwall): allow them to override ping hosts
-    let ping_hosts = default_ping_hosts;
+    let ping_hosts: Vec<&str> = PINGHOSTS.flag.split(",").collect();
     let stop_signal = Arc::new(RwLock::new(false));
 
     // Create a Registry and register metrics.
diff --git a/src/stun.rs b/src/stun.rs
index 343aa78..5ab9ffb 100644
--- a/src/stun.rs
+++ b/src/stun.rs
@@ -28,7 +28,7 @@ gflags::define! {
 }
 
 gflags::define! {
-    /// Delay between lookup attempts in seconds.
+    /// Delay between lookup attempts in seconds
     --delaySecs: u64 = 60
 }