diff --git a/examples/netstack/incremental-highlevel/demo-config.rkt b/examples/netstack/incremental-highlevel/demo-config.rkt
index b082398..33365eb 100644
--- a/examples/netstack/incremental-highlevel/demo-config.rkt
+++ b/examples/netstack/incremental-highlevel/demo-config.rkt
@@ -3,6 +3,7 @@
 
 (require racket/match)
 (require (only-in mzlib/os gethostname))
+(require (only-in racket/string string-split))
 (require "configuration.rkt")
 
 (spawn
@@ -12,7 +13,7 @@
     (assert (gateway-route (bytes 0 0 0 0) 0 (bytes 129 10 115 1) "eth0"))]
    [other ;; assume a private network
     (define interface
-      (match other
+      (match (car (string-split other "."))
         ["skip" "en0"]
         ["leap" "wlp4s0"] ;; wtf
         [_ "wlan0"]))
diff --git a/examples/netstack/monolithic-lowlevel/demo-config.rkt b/examples/netstack/monolithic-lowlevel/demo-config.rkt
index 96296c1..569b550 100644
--- a/examples/netstack/monolithic-lowlevel/demo-config.rkt
+++ b/examples/netstack/monolithic-lowlevel/demo-config.rkt
@@ -4,6 +4,7 @@
 (require racket/match)
 (require syndicate/monolithic)
 (require (only-in mzlib/os gethostname))
+(require (only-in racket/string string-split))
 (require "configuration.rkt")
 
 (provide spawn-demo-config)
@@ -17,7 +18,7 @@
                        (assertion (gateway-route (bytes 0 0 0 0) 0 (bytes 129 10 115 1) "eth0")))]
            [other ;; assume a private network
             (define interface
-              (match other
+              (match (car (string-split other "."))
                 ["skip" "en0"]
                 ["leap" "wlp4s0"] ;; wtf
                 [_ "wlan0"]))