diff --git a/net_mapper.prs b/net_mapper.prs
new file mode 100644
index 0000000..bb2a785
--- /dev/null
+++ b/net_mapper.prs
@@ -0,0 +1,2 @@
+version 1.
+RoundTripTime = <rtt @address string @minimum float @average float @maximum float>.
diff --git a/src/net_mapper.nim b/src/net_mapper.nim
new file mode 100644
index 0000000..7da129e
--- /dev/null
+++ b/src/net_mapper.nim
@@ -0,0 +1,169 @@
+# SPDX-FileCopyrightText: ☭ Emery Hemingway
+# SPDX-License-Identifier: Unlicense
+
+## A ping utility for Syndicate.
+
+import std/[asyncdispatch, asyncnet, math, monotimes, nativesockets, net, os, strutils, tables, times]
+import preserves
+import syndicate, syndicate/patterns
+
+import ./schema/net_mapper
+
+type ListenOn* {.preservesRecord: "listen-on".} = ref object
+  dataspace: Preserve[Ref]
+
+#[
+var
+  SOL_IP {.importc, nodecl, header: "<sys/socket.h>".}: int
+  IP_TTL {.importc, nodecl, header: "<netinet/in.h>".}: int
+]#
+
+proc toPreserveHook(address: IpAddress; E: typedesc): Preserve[E] = toPreserve($address, E)
+
+proc fromPreserveHook[E](address: var IpAddress; pr: Preserve[E]): bool =
+  try:
+    if pr.isString:
+      address = parseIpAddress(pr.string)
+      result = true
+  except ValueError: discard
+
+when isMainModule:
+  # verify that the hook catches
+  var ip: IpAddress
+  assert fromPreserveHook(ip, toPreserveHook(ip, void))
+
+type
+  IcmpHeader {.packed.} = object
+    `type`: uint8
+    code: uint8
+    checksum: uint16
+
+  IcmpEchoFields {.packed.} = object
+    header: IcmpHeader
+    identifier: array[2, byte]
+    sequenceNumber: uint16
+
+  IcmpEcho {.union.} = object
+    fields: IcmpEchoFields
+    buffer: array[8, uint8]
+
+  IcmpTypes = enum
+    icmpEchoReply = 0,
+    icmpEcho = 8,
+
+proc initIcmpEcho(): IcmpEcho =
+  result.fields.header.`type` = uint8 icmpEcho
+  # doAssert urandom(result.fields.identifier) # Linux does this?
+
+proc updateChecksum(msg: var IcmpEcho) =
+  var sum: uint32
+  msg.fields.header.checksum = 0
+  for n in cast[array[4, uint16]](msg.buffer): sum = sum + uint32(n)
+  while (sum and 0xffff0000'u32) != 0:
+    sum = (sum and 0xffff) + (sum shr 16)
+  msg.fields.header.checksum = not uint16(sum)
+
+proc match(a, b: IcmpEchoFields): bool =
+  ({a.header.type, b.header.type} == {uint8 icmpEcho, uint8 icmpEchoReply}) and
+    (a.header.code == b.header.code) and
+      (a.sequenceNumber == b.sequenceNumber)
+
+type
+  Pinger = ref object
+    facet: Facet
+    ds: Ref
+    rtt: RoundTripTime
+    rttHandle: Handle
+    sum: Duration
+    count: int64
+    msg: IcmpEcho
+    socket: AsyncSocket
+    sad: Sockaddr_storage
+    sadLen: SockLen
+    interval: Duration
+
+proc newPinger(address: IpAddress; facet: Facet; ds: Ref): Pinger =
+  result = Pinger(
+    facet: facet,
+    ds: ds,
+    rtt: RoundTripTime(address: $address),
+    msg: initIcmpEcho(),
+    socket: newAsyncSocket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP, false, true),
+    interval: initDuration(milliseconds = 500))
+  toSockAddr(address, Port 0, result.sad, result.sadLen)
+  # setSockOptInt(getFd socket, SOL_IP, IP_TTL, _)
+
+proc close(ping: Pinger) = close(ping.socket)
+
+proc sqr(dur: Duration): Duration =
+  let us = dur.inMicroseconds
+  initDuration(microseconds = us * us)
+
+proc update(ping: Pinger; dur: Duration) {.inline.} =
+  let secs = dur.inMicroseconds.float / 1_000_000.0
+  if ping.count == 0: (ping.rtt.minimum, ping.rtt.maximum) = (secs, secs)
+  elif secs < ping.rtt.minimum: ping.rtt.minimum = secs
+  elif secs > ping.rtt.maximum: ping.rtt.maximum = secs
+  ping.sum = ping.sum + dur
+  inc ping.count
+  ping.rtt.average = inMicroseconds(ping.sum div ping.count).float / 1_000_000.0
+
+proc exchangeEcho(ping: Pinger) {.async.} =
+  inc ping.msg.fields.sequenceNumber
+  # updateChecksum(ping.msg) # Linux does this?
+  let
+    a = getMonoTime()
+    r = sendto(ping.socket.getFd,
+      unsafeAddr ping.msg.buffer[0], ping.msg.buffer.len, 0,
+      cast[ptr SockAddr](unsafeAddr ping.sad), # neckbeard loser API
+    ping.sadLen)
+  if r == -1'i32:
+    let osError = osLastError()
+    raiseOSError(osError)
+  while true:
+    var
+      (data, address, _) = await recvFrom(ping.socket, 128)
+      b = getMonoTime()
+    if address != $ping.rtt.address:
+      stderr.writeLine "want ICMP from ", ping.rtt.address, " but received from ", address, " instead"
+    elif data.len >= ping.msg.buffer.len:
+      let
+        period = b - a
+        resp = cast[ptr IcmpEcho](unsafeAddr data[0])
+      if match(ping.msg.fields, resp.fields):
+        update(ping, period)
+        return
+      else:
+        stderr.writeLine "ICMP mismatch"
+    else:
+      stderr.writeLine "reply data has a bad length ", data.len
+
+proc kick(ping: Pinger) =
+  if not ping.socket.isClosed:
+    addTimer(ping.interval.inMilliseconds.int, oneshot = true) do (fd: AsyncFD) -> bool:
+      exchangeEcho(ping).addCallback do (fut: Future[void]):
+        if fut.failed and ping.rttHandle != Handle(0):
+          ping.facet.run do (turn: var Turn):
+            retract(turn, ping.rttHandle)
+            reset ping.rttHandle
+        else:
+          ping.facet.run do (turn: var Turn):
+            replace(turn, ping.ds, ping.rttHandle, ping.rtt)
+        if ping.interval < initDuration(seconds = 20):
+          ping.interval = ping.interval * 2
+        kick(ping)
+
+type RefArgs {.preservesDictionary.} = object
+  dataspace: Ref
+
+runActor("main") do (root: Ref; turn: var Turn):
+  connectStdio(root, turn)
+  let rttObserver = ?Observe(pattern: !RoundTripTime) ?? {0: grabLit()}
+  during(turn, root, ?RefArgs) do (ds: Ref):
+    during(turn, ds, rttObserver) do (address: IpAddress):
+      var ping: Pinger
+      if address.family == IpAddressFamily.IPv4:
+        ping = newPinger(address, turn.facet, ds)
+        kick(ping)
+    do:
+      if not ping.isNil: close(ping)
diff --git a/src/schema/net_mapper.nim b/src/schema/net_mapper.nim
new file mode 100644
index 0000000..f1201da
--- /dev/null
+++ b/src/schema/net_mapper.nim
@@ -0,0 +1,16 @@
+
+import
+  preserves
+
+type
+  RoundTripTime* {.preservesRecord: "rtt".} = object
+    `address`*: string
+    `minimum`*: float32
+    `average`*: float32
+    `maximum`*: float32
+
+proc `$`*(x: RoundTripTime): string =
+  `$`(toPreserve(x))
+
+proc encode*(x: RoundTripTime): seq[byte] =
+  encode(toPreserve(x))
diff --git a/syndicate_utils.nimble b/syndicate_utils.nimble
index ecef121..2c2381f 100644
--- a/syndicate_utils.nimble
+++ b/syndicate_utils.nimble
@@ -1,11 +1,11 @@
 # Package
 
-version = "20230518"
+version = "20230608"
 author        = "Emery Hemingway"
 description   = "Utilites for Syndicated Actors and Synit"
 license       = "unlicense"
 srcDir        = "src"
-bin           = @["json_socket_translator", "json_translator", "msg", "preserve_process_environment"]
+bin           = @["json_socket_translator", "json_translator", "msg", "net_mapper", "preserve_process_environment"]
 
 
 # Dependencies