diff --git a/src/command_parser.rs b/src/command_parser.rs
index e92e69a..db1ea8f 100644
--- a/src/command_parser.rs
+++ b/src/command_parser.rs
@@ -100,6 +100,7 @@ pub enum ShowCommand {
     Pid,
     SteinhartHart,
     PostFilter,
+    Ipv4,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -494,27 +495,32 @@ fn ipv4_addr(input: &[u8]) -> IResult<&[u8], Result<[u8; 4], Error>> {
 
 fn ipv4(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
     let (input, _) = tag("ipv4")(input)?;
-    let (input, _) = whitespace(input)?;
-    let (input, address) = ipv4_addr(input)?;
-    let (input, _) = tag("/")(input)?;
-    let (input, mask_len) = unsigned(input)?;
-    let (input, gateway) = alt((
+    alt((
         |input| {
             let (input, _) = whitespace(input)?;
-            let (input, gateway) = ipv4_addr(input)?;
-            Ok((input, gateway.map(Some)))
-        },
-        value(Ok(None), end),
-    ))(input)?;
+            let (input, address) = ipv4_addr(input)?;
+            let (input, _) = tag("/")(input)?;
+            let (input, mask_len) = unsigned(input)?;
+            let (input, gateway) = alt((
+                |input| {
+                    let (input, _) = whitespace(input)?;
+                    let (input, gateway) = ipv4_addr(input)?;
+                    Ok((input, gateway.map(Some)))
+                },
+                value(Ok(None), end),
+            ))(input)?;
 
-    let result = move || {
-        Ok(Command::Ipv4(Ipv4Config {
-            address: address?,
-            mask_len: mask_len? as u8,
-            gateway: gateway?,
-        }))
-    };
-    Ok((input, result()))
+            let result = move || {
+                Ok(Command::Ipv4(Ipv4Config {
+                    address: address?,
+                    mask_len: mask_len? as u8,
+                    gateway: gateway?,
+                }))
+            };
+            Ok((input, result()))
+        },
+        value(Ok(Command::Show(ShowCommand::Ipv4)), end),
+    ))(input)
 }
 
 fn command(input: &[u8]) -> IResult<&[u8], Result<Command, Error>> {
@@ -579,6 +585,12 @@ mod test {
         assert_eq!(command, Ok(Command::Save { channel: Some(0) }));
     }
 
+    #[test]
+    fn parse_show_ipv4() {
+        let command = Command::parse(b"ipv4");
+        assert_eq!(command, Ok(Command::Show(ShowCommand::Ipv4)));
+    }
+
     #[test]
     fn parse_ipv4() {
         let command = Command::parse(b"ipv4 192.168.1.26/24");
diff --git a/src/main.rs b/src/main.rs
index 238d88d..6823992 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -183,7 +183,7 @@ fn main() -> ! {
     let hwaddr = EthernetAddress(eui48);
     info!("EEPROM MAC address: {}", hwaddr);
 
-    net::run(clocks, dp.ETHERNET_MAC, dp.ETHERNET_DMA, eth_pins, hwaddr, ipv4_config, |iface| {
+    net::run(clocks, dp.ETHERNET_MAC, dp.ETHERNET_DMA, eth_pins, hwaddr, ipv4_config.clone(), |iface| {
         Server::<Session>::run(iface, |server| {
             leds.r1.off();
 
@@ -280,6 +280,12 @@ fn main() -> ! {
                                         }
                                     }
                                 }
+                                Command::Show(ShowCommand::Ipv4) => {
+                                    let (cidr, gateway) = net::split_ipv4_config(ipv4_config.clone());
+                                    let _ = write!(socket, "{{\"addr\":\"{}\"", cidr);
+                                    gateway.map(|gateway| write!(socket, ",\"gateway\":\"{}\"", gateway));
+                                    let _ = writeln!(socket, "}}");
+                                }
                                 Command::PwmPid { channel } => {
                                     channels.channel_state(channel).pid_engaged = true;
                                     leds.g3.on();