diff --git a/src/apps/ipfix/maps.lua b/src/apps/ipfix/maps.lua
index 01c37239c5..8b4326af5e 100644
--- a/src/apps/ipfix/maps.lua
+++ b/src/apps/ipfix/maps.lua
@@ -109,8 +109,11 @@ function mk_map(name, file, log_rate, log_fh)
       map = info.create_fn(file)
       maps[name] = map
    end
-   return { map = map,
-            logger = lib.logger_new({ rate = log_rate or 0.05,
-                                      fh = log_fh,
-                                      module = info.logger_module }) }
+   local map = { map = map }
+   if log_fh then
+      map.logger = lib.logger_new({ rate = log_rate or 0.05,
+                                    fh = log_fh,
+                                    module = info.logger_module })
+   end
+   return map
 end
diff --git a/src/apps/ipfix/template.lua b/src/apps/ipfix/template.lua
index 7ac6df4e27..6269e538bb 100644
--- a/src/apps/ipfix/template.lua
+++ b/src/apps/ipfix/template.lua
@@ -436,6 +436,10 @@ local function DNS_accumulate(self, dst, new)
    accumulate_generic(dst, new)
 end
 
+local function can_log(logger)
+   return logger and logger:can_log()
+end
+
 local function extended_extract(self, pkt, md, timestamp, entry, extract_addr_fn)
    extract_5_tuple(pkt, timestamp, entry, md, extract_addr_fn)
    local eth_hdr = ffi.cast(ether_header_ptr_t, pkt.data)
@@ -446,15 +450,17 @@ local function extended_extract(self, pkt, md, timestamp, entry, extract_addr_fn
    local result = mac_to_as.map:lookup_ptr(eth_hdr.shost)
    if result then
       entry.value.bgpPrevAdjacentAsNumber = result.value
-   elseif mac_to_as.logger:can_log() then
-      mac_to_as.logger:log("unknown source MAC "..ethernet:ntop(eth_hdr.shost))
+   elseif can_log(mac_to_as.logger) then
+      mac_to_as.logger:log("unknown source MAC "
+                              ..ethernet:ntop(eth_hdr.shost))
    end
    if not ethernet:is_mcast(eth_hdr.dhost) then
       local result = mac_to_as.map:lookup_ptr(eth_hdr.dhost)
       if result then
          entry.value.bgpNextAdjacentAsNumber = result.value
-      elseif mac_to_as.logger:can_log() then
-         mac_to_as.logger:log("unknown destination MAC "..ethernet:ntop(eth_hdr.dhost))
+      elseif can_log(mac_to_as.logger) then
+         mac_to_as.logger:log("unknown destination MAC "
+                                 ..ethernet:ntop(eth_hdr.dhost))
       end
    end
 
@@ -466,10 +472,8 @@ local function extended_extract(self, pkt, md, timestamp, entry, extract_addr_fn
       if result then
          entry.value.ingressInterface = result.ingress
          entry.value.egressInterface = result.egress
-      else
-         if vlan_to_ifindex.logger:can_log() then
-            vlan_to_ifindex.logger:log("unknown vlan "..vlan)
-         end
+      elseif can_log(vlan_to_ifindex.logger) then
+         vlan_to_ifindex.logger:log("unknown vlan "..vlan)
       end
    end
 
@@ -492,18 +496,16 @@ local function v4_extended_extract (self, pkt, timestamp, entry)
    local asn = pfx_to_as.map:search_bytes(entry.key.sourceIPv4Address)
    if asn ~= 0 then
       entry.value.bgpSourceAsNumber = asn
-   else
-      if pfx_to_as.logger:can_log() then
-         pfx_to_as.logger:log("missing AS for source "..ipv4:ntop(entry.key.sourceIPv4Address))
-      end
+   elseif can_log(pfx_to_as.logger) then
+      pfx_to_as.logger:log("missing AS for source "
+                              ..ipv4:ntop(entry.key.sourceIPv4Address))
    end
    local asn = pfx_to_as.map:search_bytes(entry.key.destinationIPv4Address)
    if asn ~= 0 then
       entry.value.bgpDestinationAsNumber = asn
-   else
-      if pfx_to_as.logger:can_log() then
-         pfx_to_as.logger:log("missing AS for destination "..ipv4:ntop(entry.key.destinationIPv4Address))
-      end
+   elseif can_log(pfx_to_as.logger) then
+      pfx_to_as.logger:log("missing AS for destination "
+                              ..ipv4:ntop(entry.key.destinationIPv4Address))
    end
 
    entry.value.ipClassOfService = get_ipv4_tos(md.l3)
diff --git a/src/program/ipfix/probe/README b/src/program/ipfix/probe/README
index b2a167d541..c37a994c24 100644
--- a/src/program/ipfix/probe/README
+++ b/src/program/ipfix/probe/README
@@ -44,11 +44,14 @@ Available options:
                                 The interval at which template records are sent in
                                 seconds. Defaults to 600.
        --pfx-to-as <file>       Name of the file that contains mappings from prefixes
-                                to AS numbers from RIR data (used by SWITCH templates)
+                                to AS numbers from RIR data (used by extended templates)
        --vlan-to-ifindex <file> Name of the file that contains mappings from VLAN
-                                tags to interface indices (used by SWITCH templates)
+                                tags to interface indices (used by extended templates)
        --mac-to-as <file>       Name of the file that contains mappings from MAC
-                                addresses to adjacent AS numbers (used by SWITCH templates)
+                                addresses to adjacent AS numbers (used by extended templates)
+       --maps-log <file>        Name of the file to which extended templates log
+                                map-related messages.  If not specified, logging is
+                                disabled.
        --netflow-v9             Use the Netflow V9 protocol to communicate to the
                                 flow collector.
        --ipfix                  Use IPFIX to communicate with the flow collector.
diff --git a/src/program/ipfix/probe/probe.lua b/src/program/ipfix/probe/probe.lua
index a2af992224..548f0d2a93 100644
--- a/src/program/ipfix/probe/probe.lua
+++ b/src/program/ipfix/probe/probe.lua
@@ -204,7 +204,7 @@ function run (args)
          end
       end,
       ["maps-log"] = function (arg)
-         if arg then
+         if arg ~= "" then
             maps_log_fh = assert(io.open(arg, "a"))
          end
       end,