On my MacBook Pro laptop running OS X El Capitan (10.11.6), I've been losing Internet connectivity periodically. Though it appears I still have Wi-Fi connectivity, when I attempt to access websites through a browser I find that I can't access sites at times, though a moment before I had no issues browsing the Web. Firefox will display a "Server not found" message. If I go to a Terminal window and try to ping any IP address, I see "request timeout" messages.
$ ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 ^C --- 8.8.8.8 ping statistics --- 3 packets transmitted, 0 packets received, 100.0% packet loss $
If I check the status of the WiFi connection using the airport command, I see that it is very noisy, though the signal stength is good, which I would expect, since the laptop is only a few feet from the wireless router.
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I
agrCtlRSSI: -39
agrExtRSSI: 0
agrCtlNoise: -93
agrExtNoise: 0
state: running
op mode: station
lastTxRate: 73
maxRate: 72
lastAssocStatus: 0
802.11 auth: open
link auth: wpa2-psk
BSSID: 94:44:52:4a:43:40
SSID: Rain
MCS: 7
channel: 11
$The above output from the command shows me that channel 11 is being used
for the wireless connection. The agrCTLRSSI value -
"RSSI" stands for received
signal strength indication - was minus 39, which isn't bad for signal
srength, since for Apple OS X systems, the closer the number is to
negative 100, the weaker the signal - see
Checking WiFi signal
strength from the command line on OS X for further information. The
noise value is represented by agrCtlNoise. In this case I saw a
value of -87; less negative values or better, so the system was
reporting a noisy signal.
When I checked the noise level again, I saw it was slightly less negative at -90 and I was still unable to ping a Google DNS server at 8.8.8.8.
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I
agrCtlRSSI: -41
agrExtRSSI: 0
agrCtlNoise: -90
agrExtNoise: 0
state: running
op mode: station
lastTxRate: 73
maxRate: 72
lastAssocStatus: 0
802.11 auth: open
link auth: wpa2-psk
BSSID: 94:44:52:5a:54:52
SSID: Maze
MCS: 7
channel: 11
$ ping -c 4 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
--- 8.8.8.8 ping statistics ---
4 packets transmitted, 0 packets received, 100.0% packet loss
$When I checked later when connectivity was present, I saw that the agrCtlNoise value was -95 indicating a very noisy conection, even noisier than when the connectivity had dropped, though.
$ ping -c 4 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=0 ttl=41 time=33.534 ms
64 bytes from 8.8.8.8: icmp_seq=1 ttl=41 time=74.867 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=41 time=86.201 ms
^C
--- 8.8.8.8 ping statistics ---
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 33.534/64.867/86.201/22.634 ms
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I
agrCtlRSSI: -40
agrExtRSSI: 0
agrCtlNoise: -95
agrExtNoise: 0
state: running
op mode: station
lastTxRate: 73
maxRate: 72
lastAssocStatus: 0
802.11 auth: open
link auth: wpa2-psk
BSSID: 94:44:52:4a:43:40
SSID: Rain
MCS: 7
channel: 11
$The connectivity will come and go on its own. If I wait a few minutes, I
may find I have connectivity again, though I can immediately restore connectivity
by clicking on the Wi-Fi icon at the top of the screen and choosing "Turn
Wi-Fi Off" and then "Turn Wi-Fi On". or I can isse the command
networksetup -setairportpower en0 off at the
Bash shell prompt
in the Terminal window followed by networksetup -setairportpower en0 on
.
Checking on other wireless networks in the vicinity, I saw the following for neighbors' Wi-Fi networks:
$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -s
SSID BSSID RSSI CHANNEL HT CC SECURITY (auth/unicast/group)
Valentine Repeater 0e:41:58:01:0a:44 -77 11,-1 Y -- WPA2(PSK/AES/AES)
NETGEAR07-5G c4:04:15:4c:fe:ea -41 153,-1 Y -- WPA2(PSK/AES/AES)
RSSYL 70:f1:96:b7:04:31 -92 6 Y -- WPA2(PSK/AES,TKIP/TKIP)
558935 0c:54:a5:48:19:e5 -35 1 Y -- WPA(PSK/AES,TKIP/TKIP) WPA2(PSK/AES,TKIP/TKIP)
NETGEAR07 c4:04:15:4c:fe:eb -34 1 Y -- WPA2(PSK/AES/AES)
Linksys08230-guest 16:91:82:68:e3:5d -84 11 Y US NONE
Valentine-2.4ghz 94:87:7c:07:f6:90 -79 11,-1 Y DF WPA(PSK/TKIP,AES/TKIP) WPA2(PSK/TKIP,AES/TKIP)
Rain 94:44:52:4a:43:40 -39 11,-1 Y -- WPA(PSK/AES/AES) WPA2(PSK/AES/AES)
$The CC column holds the country code for the router. I saw a
"DF" country
code for one nearby router. I saw
a "DF" country code when I
was noting this same problem last summer. The
"DF" in the CC field apparently represents the Mexican state Distrito Federal
- I've included the link to the document in the Internet Archive, aka the
Wayback
Machine, since, though the document was available on the FBI website in July
when I looked up the code previously, it is no longer on the FBI site.
According to the results of the wireless diagnostics check I had run from the MacBook in July, the presence of a "conflicting country code", i.e., one that differs from the country code of other wireless devices nearby, can cause problems for Apple OS X systems:
A nearby wireless router has been detected which is identifying itself as
originating from a country
which conflicts with your current settings. This may prevent your Mac from automatically re-joining
a previously joined Wi-Fi network.
Certain wireless routers have the ability to identify the country they are
designated to work in, this is
called the Country Code. Wireless routers should only be used in the country they were originally
obtained from. Failure to do so can result in performance and reliability issues for nearby wireless clients.
If possible, contact the network owner to resolve the problem.
In this case I see that the
basic service set identifier (BSSID) of the router with the country code of
DF is 94:87:7c:07:f6:90. "BSS" stands for basic service set. BSS
provides the basic building-block for an
802.11
wireless local area
network (LAN). And:
For a BSS operating in infrastructure mode, the BSSID is the MAC address of the wireless access point (WAP) generated by combining the 24 bit Organization Unique Identifier (OUI, the manufacturer's identity) and the manufacturer's assigned 24-bit identifier for the radio chipset in the WAP. The BSSID is the formal name of the BSS and is always associated with only one BSS. Note, the MAC address concept is not limited to radio communication; wired networks use the very same 24+24 bit MAC address concept to uniquely identify the hosts.
Thre are a number of online sites where you can perform MAC address and OUI lookups and a lookup on 94:87:7c:07:f6:90 shows the following:
| MAC Addres/OUI | Vendor (Company) |
|---|---|
| 94:87:7C | ARRIS Group, Inc. |
I saw this same device in July of last year, i.e., the BSSID was the same, though it appears the neighbor has changed the service set identifier (SSID) from "ARRIS-F692" to "Valentine-2.4ghz". The Arris Group is an American telecommunications company that provides network equipment to cable operators. Though the company has its headquarters in Suwanee, Georgia in the U.S., they have manufacturing, distribution, service and sales office locations in other parts of the world. The Arris website shows that they have facilities in the following locations in Mexico:
Apodaca
México City
Tijuana
At Template:Mexico State-Abbreviation Codes, I see the following:
| Name of federative entity | Conventional abbreviation | 2-letter code* | 3-letter code (ISO 3166-2:MX) |
|---|---|---|---|
 Federal District (Mexico City) |
D.F. or CDMX | MX - DF | MX-DIF |
*Mexico's post agency, Correos de México, does not offer an official list. Various competing commercially devised lists exist. The list here reflects choices among them according to these sources.
I know that the local cable company, Atlantic Broadband, deploys Arris network gear for some of its home users. Unfortunately, though, I don't know if there is anything I can do to easily resolve this problem; I may run a cable from a router to the MacBook Pro and use a wired connection, instead. A How-to Geek article on the problem, How to Fix Conflicting Country Codes and Improve Your Mac’s Wi-Fi notes:
Unfortunately, there doesn’t seem to be a way to force your Mac to listen to only a specific country code. There’s no clear way to prefer a particular country code when multiple ones are nearby. The only real solution is to locate the offending wireless router and either change its country code or replace it with a router that’s properly configured to operate in your current country.
This may be a problem. Unless the router belongs to you or someone else you know, there may not be much you can do about this. You could walk around with your laptop or phone, looking for where the signal appears strongest and knocking on your neighbors’ doors to locate the rogue Wi-Fi network and ask your neighbor to fix it. It sounds like a ridiculous solution, but that’s what Apple recommends — as the Wi-Fi Diagnostics app says, you should “contact the network owner to resolve the problem.” It’s not an easy solution, or even a realistic one in many situations, but it’s the only one that will work.
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