diff --git a/src/libstore/ssh.cc b/src/libstore/ssh.cc
index 00fd25dd293..0d3c4eeb5b4 100644
--- a/src/libstore/ssh.cc
+++ b/src/libstore/ssh.cc
@@ -3,18 +3,16 @@
 namespace nix {
 
 SSHMaster::SSHMaster(const std::string & hostNport, const std::string & keyFile, bool useMaster, bool compress, int logFD)
-    : fakeSSH(host == "localhost")
-    , keyFile(keyFile)
+    : keyFile(keyFile)
     , useMaster(useMaster && !fakeSSH)
     , compress(compress)
     , logFD(logFD)
 {
-    auto res = split(hostNport, *":");
-    port = res.size() > 0 ? atoi(res[1].c_str()) : 0;
+    auto res = split(hostNport, ':');
+    port = res.size() > 1 ? atoi(res[1].c_str()) : 0; // if we have a port, parse that
     host = res[0];
 
-    // help: is this above already using the actual value or is it broken without this
-    fakeSSH = host == "localhost";
+    fakeSSH = host == "localhost" && !port;
 
     if (host == "" || hasPrefix(host, "-"))
         throw Error("invalid SSH host name '%s'", host);