diff --git a/cmd/tailscale/tailscale.go b/cmd/tailscale/tailscale.go
index 57db63be8..96751d5d3 100644
--- a/cmd/tailscale/tailscale.go
+++ b/cmd/tailscale/tailscale.go
@@ -18,7 +18,6 @@ import (
 	"syscall"
 
 	"github.com/apenwarr/fixconsole"
-	"github.com/pborman/getopt/v2"
 	"github.com/peterbourgon/ff/v2/ffcli"
 	"github.com/tailscale/wireguard-go/wgcfg"
 	"tailscale.com/ipn"
@@ -120,7 +119,7 @@ var upArgs = struct {
 func runUp(ctx context.Context, args []string) error {
 	pol := logpolicy.New("tailnode.log.tailscale.io")
 	if len(args) > 0 {
-		log.Fatalf("too many non-flag arguments: %#v", getopt.Args()[0])
+		log.Fatalf("too many non-flag arguments: %q", args)
 	}
 
 	defer pol.Close()
@@ -149,7 +148,7 @@ func runUp(ctx context.Context, args []string) error {
 
 	c, err := safesocket.Connect(upArgs.socket, 41112)
 	if err != nil {
-		log.Fatalf("safesocket.Connect: %v\n", err)
+		log.Fatalf("Failed to connect to connect to tailscaled. (safesocket.Connect: %v)\n", err)
 	}
 	clientToServer := func(b []byte) {
 		ipn.WriteMsg(c, b)
diff --git a/control/controlclient/auto_test.go b/control/controlclient/auto_test.go
index 7ebcfb302..d4a090a37 100644
--- a/control/controlclient/auto_test.go
+++ b/control/controlclient/auto_test.go
@@ -348,6 +348,53 @@ func TestControl(t *testing.T) {
 		c3.checkNoStatus(t)
 		c4.checkNoStatus(t)
 	})
+
+	t.Run("set hostinfo", func(t *testing.T) {
+		c1.SetHostinfo(&tailcfg.Hostinfo{
+			BackendLogID: "set-hostinfo-test",
+			OS:           "linux",
+		})
+		c1.waitStatus(t, stateSynchronized)
+		c2NetMap := c2.status(t).New.NetMap
+		if len(c2NetMap.Peers) != 1 {
+			t.Fatalf("wrong number of peers: %v", c2NetMap.Peers)
+		}
+		peer := c2NetMap.Peers[0]
+		if !peer.KeepAlive {
+			t.Errorf("peer KeepAlive=false, want true")
+		}
+		if peer.Hostinfo.OS != "linux" {
+			t.Errorf("peer hostinfo does not have OS: %v", peer.Hostinfo)
+		}
+
+		c2.SetHostinfo(&tailcfg.Hostinfo{
+			BackendLogID: "set-hostinfo-test",
+			OS:           "iOS",
+		})
+		c1NetMap = c1.status(t).New.NetMap
+		c2NetMap = c2.status(t).New.NetMap
+		if len(c1NetMap.Peers) != 1 {
+			t.Fatalf("wrong number of peers: %v", c1NetMap.Peers)
+		}
+		if len(c2NetMap.Peers) != 1 {
+			t.Fatalf("wrong number of peers: %v", c2NetMap.Peers)
+		}
+		peer = c1NetMap.Peers[0]
+		if peer.KeepAlive {
+			t.Errorf("peer KeepAlive=true, want false")
+		}
+		if peer.Hostinfo.OS != "iOS" {
+			t.Errorf("peer hostinfo does not have OS: %v", peer.Hostinfo)
+		}
+		peer = c2NetMap.Peers[0]
+		if peer.KeepAlive {
+			t.Errorf("peer KeepAlive=true, want false")
+		}
+		if peer.Hostinfo.OS != "linux" {
+			t.Errorf("peer hostinfo does not have OS: %v", peer.Hostinfo)
+		}
+
+	})
 }
 
 func hasStringsSuffix(list, suffix []string) bool {
diff --git a/control/controlclient/netmap.go b/control/controlclient/netmap.go
index ac1c44081..7a5c36eea 100644
--- a/control/controlclient/netmap.go
+++ b/control/controlclient/netmap.go
@@ -16,7 +16,6 @@ import (
 
 	"github.com/tailscale/wireguard-go/wgcfg"
 	"tailscale.com/tailcfg"
-	"tailscale.com/version"
 	"tailscale.com/wgengine/filter"
 )
 
@@ -328,8 +327,7 @@ func (nm *NetworkMap) _WireGuardConfig(uflags int, dnsOverride []wgcfg.IP, allEn
 			aips = append(aips, aip)
 		}
 		fmt.Fprintf(buf, "AllowedIPs = %s\n", strings.Join(aips, ", "))
-		doKeepAlives := !version.IsMobile()
-		if doKeepAlives {
+		if peer.KeepAlive {
 			fmt.Fprintf(buf, "PersistentKeepalive = 25\n")
 		}
 	}
diff --git a/logtail/logtail.go b/logtail/logtail.go
index 77c6ca023..f63948e48 100644
--- a/logtail/logtail.go
+++ b/logtail/logtail.go
@@ -169,7 +169,8 @@ func (l *logger) drainPending() (res []byte) {
 	entries := 0
 
 	var batchDone bool
-	for buf.Len() < 1<<18 && !batchDone {
+	const maxLen = 256 << 10
+	for buf.Len() < maxLen && !batchDone {
 		b, err := l.buffer.TryReadLine()
 		if err == io.EOF {
 			break
@@ -292,7 +293,7 @@ func (l *logger) upload(ctx context.Context, body []byte) (uploaded bool, err er
 	if resp.StatusCode != 200 {
 		uploaded = resp.StatusCode == 400 // the server saved the logs anyway
 		b, _ := ioutil.ReadAll(resp.Body)
-		return uploaded, fmt.Errorf("log upload of %d bytes %s failed %d: %q", len(body), compressedNote, resp.StatusCode, string(b))
+		return uploaded, fmt.Errorf("log upload of %d bytes %s failed %d: %q", len(body), compressedNote, resp.StatusCode, b)
 	}
 	return true, nil
 }
@@ -402,10 +403,8 @@ func (l *logger) Write(buf []byte) (int, error) {
 		} else {
 			// The log package always line-terminates logs,
 			// so this is an uncommon path.
-			bufnl := make([]byte, len(buf)+1)
-			copy(bufnl, buf)
-			bufnl[len(bufnl)-1] = '\n'
-			l.stderr.Write(bufnl)
+			withNL := append(buf[:len(buf):len(buf)], '\n')
+			l.stderr.Write(withNL)
 		}
 	}
 	b := l.encode(buf)
diff --git a/stun/stun.go b/stun/stun.go
index f0b114406..d6b6e7856 100644
--- a/stun/stun.go
+++ b/stun/stun.go
@@ -124,7 +124,7 @@ func ParseBindingRequest(b []byte) (TxID, error) {
 
 var (
 	ErrNotSTUN            = errors.New("response is not a STUN packet")
-	ErrNotSuccessResponse = errors.New("STUN response error")
+	ErrNotSuccessResponse = errors.New("STUN packet is not a response")
 	ErrMalformedAttrs     = errors.New("STUN response has malformed attributes")
 	ErrNotBindingRequest  = errors.New("STUN request not a binding request")
 	ErrWrongSoftware      = errors.New("STUN request came from non-Tailscale software")
diff --git a/stunner/stunner.go b/stunner/stunner.go
index 00e8318a9..534f617f9 100644
--- a/stunner/stunner.go
+++ b/stunner/stunner.go
@@ -110,7 +110,7 @@ func (s *Stunner) Receive(p []byte, fromAddr *net.UDPAddr) {
 			// check probe coming in late. Ignore.
 			return
 		}
-		s.logf("stunner: received bad STUN response: %v", err)
+		s.logf("stunner: received unexpected STUN message response from %v: %v", fromAddr, err)
 		return
 	}
 	r, ok := s.removeTX(tx)
diff --git a/tailcfg/tailcfg.go b/tailcfg/tailcfg.go
index cd2fef1bf..00ecaa74e 100644
--- a/tailcfg/tailcfg.go
+++ b/tailcfg/tailcfg.go
@@ -134,6 +134,8 @@ type Node struct {
 	Created    time.Time
 	LastSeen   *time.Time `json:",omitempty"`
 
+	KeepAlive bool // open and keep open a connection to this peer
+
 	MachineAuthorized bool // TODO(crawshaw): replace with MachineStatus
 
 	// NOTE: any new fields containing pointers in this type
diff --git a/tailcfg/tailcfg_test.go b/tailcfg/tailcfg_test.go
index 32f30dbdb..3bca304c1 100644
--- a/tailcfg/tailcfg_test.go
+++ b/tailcfg/tailcfg_test.go
@@ -160,7 +160,7 @@ func TestHostinfoEqual(t *testing.T) {
 }
 
 func TestNodeEqual(t *testing.T) {
-	nodeHandles := []string{"ID", "Name", "User", "Key", "KeyExpiry", "Machine", "Addresses", "AllowedIPs", "Endpoints", "DERP", "Hostinfo", "Created", "LastSeen", "MachineAuthorized"}
+	nodeHandles := []string{"ID", "Name", "User", "Key", "KeyExpiry", "Machine", "Addresses", "AllowedIPs", "Endpoints", "DERP", "Hostinfo", "Created", "LastSeen", "KeepAlive", "MachineAuthorized"}
 	if have := fieldsOf(reflect.TypeOf(Node{})); !reflect.DeepEqual(have, nodeHandles) {
 		t.Errorf("Node.Equal check might be out of sync\nfields: %q\nhandled: %q\n",
 			have, nodeHandles)
diff --git a/version/version.go b/version/version.go
index 3d7537d5e..b35558a7d 100644
--- a/version/version.go
+++ b/version/version.go
@@ -7,5 +7,5 @@
 // Package version provides the version that the binary was built at.
 package version
 
-const LONG = "date.20200311"
+const LONG = "date.20200315"
 const SHORT = LONG // TODO: unused; remove SHORT? Make it a func?