Since yesterday (when my internet provider had some maintenance) my mac book pro (el capitan 10.11.4) has some problems with the Wifi, here's an extract of me pinging google.com via wifi:
Request timeout for icmp_seq 382
Request timeout for icmp_seq 383
Request timeout for icmp_seq 384
Request timeout for icmp_seq 385
Request timeout for icmp_seq 386
Request timeout for icmp_seq 387
Request timeout for icmp_seq 388
Request timeout for icmp_seq 389
64 bytes from 216.58.213.174: icmp_seq=390 ttl=52 time=20.415 ms
64 bytes from 216.58.213.174: icmp_seq=391 ttl=52 time=17.444 ms
64 bytes from 216.58.213.174: icmp_seq=392 ttl=52 time=17.749 ms
64 bytes from 216.58.213.174: icmp_seq=393 ttl=52 time=19.289 ms
64 bytes from 216.58.213.174: icmp_seq=394 ttl=52 time=19.362 ms
64 bytes from 216.58.213.174: icmp_seq=395 ttl=52 time=17.343 ms
64 bytes from 216.58.213.174: icmp_seq=396 ttl=52 time=17.524 ms
64 bytes from 216.58.213.174: icmp_seq=397 ttl=52 time=17.598 ms
64 bytes from 216.58.213.174: icmp_seq=398 ttl=52 time=18.027 ms
64 bytes from 216.58.213.174: icmp_seq=399 ttl=52 time=20.015 ms
64 bytes from 216.58.213.174: icmp_seq=400 ttl=52 time=19.273 ms
64 bytes from 216.58.213.174: icmp_seq=401 ttl=52 time=18.544 ms
64 bytes from 216.58.213.174: icmp_seq=402 ttl=52 time=25.108 ms
64 bytes from 216.58.213.174: icmp_seq=403 ttl=52 time=18.939 ms
64 bytes from 216.58.213.174: icmp_seq=404 ttl=52 time=17.232 ms
64 bytes from 216.58.213.174: icmp_seq=405 ttl=52 time=18.307 ms
Request timeout for icmp_seq 406
Request timeout for icmp_seq 407
Request timeout for icmp_seq 408
Request timeout for icmp_seq 409
Request timeout for icmp_seq 410
Request timeout for icmp_seq 411
Request timeout for icmp_seq 412
Request timeout for icmp_seq 413
Request timeout for icmp_seq 414
Request timeout for icmp_seq 415
Request timeout for icmp_seq 416
Request timeout for icmp_seq 417
Request timeout for icmp_seq 418
Request timeout for icmp_seq 419
64 bytes from 216.58.213.174: icmp_seq=420 ttl=52 time=34.529 ms
64 bytes from 216.58.213.174: icmp_seq=421 ttl=52 time=18.739 ms
64 bytes from 216.58.213.174: icmp_seq=422 ttl=52 time=18.910 ms
64 bytes from 216.58.213.174: icmp_seq=423 ttl=52 time=18.611 ms
64 bytes from 216.58.213.174: icmp_seq=424 ttl=52 time=18.644 ms
64 bytes from 216.58.213.174: icmp_seq=425 ttl=52 time=21.250 ms
64 bytes from 216.58.213.174: icmp_seq=426 ttl=52 time=18.318 ms
64 bytes from 216.58.213.174: icmp_seq=427 ttl=52 time=18.222 ms
64 bytes from 216.58.213.174: icmp_seq=428 ttl=52 time=19.886 ms
64 bytes from 216.58.213.174: icmp_seq=429 ttl=52 time=18.250 ms
64 bytes from 216.58.213.174: icmp_seq=430 ttl=52 time=19.456 ms
^C
--- google.com ping statistics ---
431 packets transmitted, 190 packets received, 55.9% packet loss
round-trip min/avg/max/stddev = 17.086/27.479/303.490/32.073 ms
The wifi connection on the bar is never lost during this time, (and it's shown always with top quality), though still the packets are lost. In the moments where the ping doesn't work the computer is offline (i.e. I can't surf, send emails or anything).
The problem doesn't happen when the computer is connected directly to the router via an Ethernet cable, and I have another mac (10.9.5 Mavericks) that doesn't have the problem with the wifi at all.
I've contacted the internet provider and they checked everything and mentioned that the problem is with my computer.
I had this same issue yesterday, and following this procedure to reset the wifi hardware, and it fixed the problem, until this morning, when I got back to my computer, and I was back to square one, with the problem happening again.
--- addition:
the router is a Netgear VMDG490, Software Version "V1.01.11", Hardware Version: 1.03
This week I'm working from a different network and problem happens again: the internet works fine for a while, and then after some 10/20 minutes the ping (which nowadays is always on) stops working for several minutes, and my computer gets offline, when this happens I tried pinging the router, and there is connection to it, so my computer is connected to the router, but I cannot get beyond it.
With this network the problem is somewhat different, as the network stays connected for way longer before giving the issue, and disconnects way longer. If I disconnect the wifi and reactivate it then the computer connects fine, and for the 10/20 minutes it works fine.
I tried running the diagnostics on the wifi network and that seems to be fixing the problem for 20 minutes more.
When I am in the office my wifi had no problems at all.
My computer is also configured with tunnelblick to access the office VPN when I'm working remotely (and when I use it it disconnects too)
216.58.213.174is an external address. Pings to it will be subject to additional external factors you have no control over. You should re-run your ping test to the router address. If there are no drop outs the issues are with your ISP.