News for hackers. Stuff that matters.
Re:Resolving an unusual WiFi issue by AnotherGoodName on Friday August 19, 2022 @03:54PM (#32525330)
Anyone ever had arp storms on a home network?

I've had something trigger every device into asking 'who has xyz ip tell [Mac]'. It made the network unusable and even rebooting systems it would come back since as soon as one device asked the question (sent the broken arp packet) all other devices decided they too needed to know.

The solution that worked was to flip the circuit breaker for the whole house and reset every network device at once.

Re:Resolving an unusual WiFi issue by klysm on Friday August 19, 2022 @03:59PM (#32525369)
I haven’t had a problem where rebooting the house has fixed it thankfully
Re:Resolving an unusual WiFi issue by somat on Saturday August 20, 2022 @12:01AM (#32528951)
I laughed, but it made me think, with "smart" houses becoming a thing, this will one day become a common occurrence. sigh
Re:Resolving an unusual WiFi issue by eikenberry on Friday August 19, 2022 @04:45PM (#32525716)
I have had 2 external USB-power-passthrough laptop doc/hub things with an Ethernet port. They both cause a packet storm on the network if you unplug the computer and leave the ethernet and power plugged in. Causes all my crappy realtek NICs to overheat and flake out. Not exactly the same but super annoying.
Re:Resolving an unusual WiFi issue by jfim on Friday August 19, 2022 @04:58PM (#32525835)
I had the same issue with an USB Ethernet adapter plugged into a powered USB hub, disconnecting the computer would make the network crap out. Kind of defeats the purpose of having a docked setup with wired Ethernet if one can't undock it or needs to unplug tons of cables each time.
Re:Resolving an unusual WiFi issue by smashed on Friday August 19, 2022 @09:13PM (#32528061)
See Ethernet pause frames

Usb ethernet adapters will send these pause frames, waiting for the computer to reconnect.. but they end up flooding dumb switches..

https://news.ycombinator.com/item?id=31268134

Re:Resolving an unusual WiFi issue by evulhotdog on Friday August 19, 2022 @10:21PM (#32528404)
Yep. There’s actually a known issue with the CalDigit USB C Pro dock that causes this. It’s when the laptop comes up from or goes to sleep and it takes down the whole network. Fortunately there’s a firmware fix for it but it took a while to put two and two together.
Re:Resolving an unusual WiFi issue by danieldk on Saturday August 20, 2022 @03:45AM (#32530114)
I think more adapters/docks with an RTL8153 suffer from this issue. E.g., I had a Lenovo USB-C Gen 2 dock that would fairly reliably take down our office network after suspend-wake. Just avoid Realtek NICs like the plague.
Re:Resolving an unusual WiFi issue by zamadatix on Friday August 19, 2022 @10:39PM (#32528489)
I thought the dock thing was related to excessively sending pause frames to switches that didn't know to not forward them.
Re:Resolving an unusual WiFi issue by evulhotdog on Friday August 19, 2022 @10:45PM (#32528521)
Re:Resolving an unusual WiFi issue by iforgotpassword on Saturday August 20, 2022 @02:55AM (#32529851)
This freaking issue! This has plagued humanity for decades now I think. I had an older ThinkPad at work once that did that when it went to sleep. Fun for the whole fami^Wgroup of colleagues sharing the switch. Pause frames must die, leave flow control to a higher layer.
Re:Resolving an unusual WiFi issue by Abishek_Muthian on Saturday August 20, 2022 @10:16AM (#32532196)
I had a Apple USB 2.0 USB dongle which would crash the OSX when the router (DDWRT) is rebooted and sometimes would crash the router when the system was rebooted. Didn't do that with other combinations of OS/Router.

Bug bounty opportunity missed?

Re:Resolving an unusual WiFi issue by rob_c on Saturday August 20, 2022 @10:49AM (#32532437)
If this wasn't a poor mains system that's closer to a physical DoS attack vector which is with more than a bug bounty if you ever narrowed it down.

Think of the number of meetings that could be cut short by the ohp system crashing, the many hours that's could be saved :p

Re:Resolving an unusual WiFi issue by comprambler on Friday August 19, 2022 @07:04PM (#32527140)
Similar, but not exact, are deb, and likely others, with failed storage will continually dhcprenew as they can’t write the leasefile for the interface. Near ddos as far as windows dhcp server is concerned. Required an arp table trace to find. Bad_Address is usually the symptom.
Re:Resolving an unusual WiFi issue by xoa on Friday August 19, 2022 @05:03PM (#32525866)
Depending on what network gear you're using (I'm now switching to Omada, previously/still on some site son UniFi, but lots of even 'prosumer' stuff does this) there are specific mitigations available. All of this falls under the heading of "managing broadcast traffic", which is very important even for smaller networks. The three major categories of traffic on a network are unicast, broadcast, and multicast. Unicast is the normal case of one device talking to a single address. Broadcast involves sending a packet to every single possible recipient in the entire broadcast domain (almost always the subnet). ARP fits in here. Multicast is essentially in between, more efficient then broadcast, can still talk to multiple devices that have signed up to hear it.

Obviously an actual broadcast storm can take down an entire network, but excessive broadcast traffic on WiFi specifically can also suck up a huge amount of airtime for little bandwidth. Every single device has to go to the slowest speed and stop what they're doing to listen and make sure no one is left out. Using STP/RSTP with proper values set and LACP for aggregated interfaces can help prevent inadvertent network loops. Many switches also support some kind of port isolation and explicit per port storm control restricting max numbers of packets/second for unicast/broadcast/multicast traffic. WiFi APs can use proxy ARP to cut it in their domain too. The WAP already of course knows the MACs of every device connected to it by definition, so there isn't generally any reason not to have it answer ARP requests on their behalf then forward the traffic itself.

Re:Resolving an unusual WiFi issue by zamadatix on Friday August 19, 2022 @10:54PM (#32528582)
For home I wouldn't really bother with storm control. In the rare case something is actually misbehaving in that regard it's not much work to go fix right and I'd rather do that than mask it with storm control so it's still happening just not enough to cause an obvious signal.

For home wireless another trick, assuming you have a higher end model, is setting it to a different network than the wired. If you're not in particular need for slow service at the very edge of the coverage zone you can also raise the minimum data rate and then BUM traffic and wireless management frames won't be as painful even when they do occur.

Re:Resolving an unusual WiFi issue by vladvasiliu on Saturday August 20, 2022 @05:40AM (#32530726)
> In the rare case something is actually misbehaving in that regard it's not much work to go fix right and I'd rather do that than mask it with storm control so it's still happening just not enough to cause an obvious signal.

While I agree with the general idea, I think that there are only so many hours in a day. If the broken device isn't easily fixable, like most IoT junk out there, it's nice to be able to limit the damage.

Re:Resolving an unusual WiFi issue by zamadatix on Sunday August 21, 2022 @01:48AM (#32537729)
There are better network only solutions for unfixable devices when you have that class of gear, such as moving it to its own VLAN which is a good practice for even properly functioning IoT devices.

Storm control has more a "John brought a home Netgear (which ignores but doesn't forward spanning tree packets) and created a loop between two wallports despite spanning tree being enabled on them. Thanks to storm control Jane is still able use her IP phone for a meeting while the network admin investigates a monitoring alert about excessive broadcast drops on John's port which is causing slowdowns in that network" type use case. It's not meant to be the long term solution to anything it's just there for when other long term solutions fail to kick in and you don't want a full outage until you can fix them.

Re:Resolving an unusual WiFi issue by donmcronald on Friday August 19, 2022 @05:21PM (#32526053)
Why the switch to Omada? I’m looking at doing the same due to supply issues with the UniFi stuff. Any tips or opinions on Omada vs UniFi?
Re:Resolving an unusual WiFi issue by xoa on Friday August 19, 2022 @06:01PM (#32526494)
Opinions hooboy do I have them ;), I was just asked that exact question on HN a couple of weeks ago in fact. Gave it a shot in a response here [0] which still applies. But basically Ubiquiti has become a toxic dumpster fire of a company and their product lines (UniFi in particular) on a downward trajectory in terms of performance, features and stability for quite a while. I had a certain amount invested in UniFi (think the final total will end up as a few hundred devices) so it's been a staged switch, with a total change of all routing/gateway/security functions to OPNsense completed first. That bought a lot more runway, it's always been the weakest and most neglected area in the ecosystem while obviously also being pretty critical. Yet the Ubiquiti debacle has served to underline for me how valuable self-host is, I've been able to have a nice slow ramp and deal with their implosion precisely because UniFi/UNMS/UISP and all the hardware is fully under my control. So I've been hoping someone would come along and see the potential of the UniFi niche of the networking market and basically copy it without all the junk. Which seems to basically be Omada to a tee.

I'd actually originally (and still at many sites) intended to hold off and wait for WiFi 7 gear, because at that point a bunch of clients (and myself for that matter) will be interested in replacing WAPs anyway which is a very natural point to consider changing manufacturer as well. But a breaking point has come at a few places with a final feature which is PPSK, allowing the system to have many different passwords for an SSID that can be assigned different tags. Basically it allows having many of the benefits of WPA-Enterprise in terms of segmenting different clients onto different VLANs and revoking credentials and the like with more security and less manual work than MAB (MAC bypass) while still looking like a normal PSK scheme, which means the vast universe of brand new stuff which doesn't support 802.1x and never will works with it happily (by the same token none of that is going to play directly with using a secure virtual network or other better systems either sadly). Lower overhead and better compatibility than captive portals for non or semi-interactive devices as well. Someone hacked together a demo showing this could work on UniFi WAPs like four freaking years ago and Ubiquiti never did anything with it in favor of endless bikeshedding GUI changes to add more white space and hide important features and information (yes I'm a touch bitter).

So I'm not in the position of wholeheartedly recommending Omada yet, I don't have years under my belt there and it's relatively speaking fairly new. It has its own warts and rough edges for sure, from the software to the hardware physical design. But it can be self-hosted and the trajectory looks massively better, has already had more meaningful improvement in months than UniFi has had in years, seems to perform much better so far as well.

Of course the Venn diagram of self-hosting, herding lots of hardware with single pane, fully networking features, ecosystem richness and so on is pretty minimal in the overlap. Take away any one or multiple of those and options expand a lot, Aruba InstantOn for example.

And welp, this didn't end up "basically" at all did it, sorry about that. I am bummed by the sheer wasted potential with Ubiquiti. So it goes in tech over and over again though, we've all seen this movie many, many times.

As far as tips, I would suggest if you plan to stay on the managing-your-own-networks route to very strongly consider having the router/gateway stuff be separate and fully open source as I ended up. Doesn't have to be OPNsense, could be VyOS or plain OpenBSD or whatever else you're most comfortable with and depending on how you want to manage stuff and what needs there are for others to take over. But it's very, very pleasant to have the full spectrum of quality PC hardware available, you can get far more power for less, and you're never stuck with a critical aspect. I'd still suggest generally running that on metal rather than virtualizing it in a (semi)production network, but opinions vary there.

----

0: https://news.ycombinator.com/item?id=32297556

Re:Resolving an unusual WiFi issue by donmcronald on Friday August 19, 2022 @08:07PM (#32527601)
Thanks for taking the time to reply.

I've also soured on UniFi a lot over the last few years. It's crazy. The SMB / MSP market is massively underserved and instead of staying focused and capturing it Unifi is trying to compete in the enterprise market where, IMHO, they aren't going to succeed.

If we try out Omada and feel like it gives us everything Unifi does without all the feature creep then we'll do the same thing as you; EoL sites will move from Unifi to Omada. I'll always take fewer features and stability over continuous new features.

> I would suggest if you plan to stay on the managing-your-own-networks route to very strongly consider having the router/gateway stuff be separate and fully open source as I ended up.

We've used pfSense forever and have been happy with it. However, 2.6.0 has some gateway/dpinger issues where the bug fixes are slotted for 2.7.0 on the CE side, so it feels like the inevitable neglect of the CE version might be starting to kick in there. I tried to explain to them the realities of the market we're in (small businesses) along with real numbers in terms of what kind of money they could extract from businesses like ours and all it got me was an offer to talk to someone in sales and we're not buying into subscriptions (ever).

It would cost us $15k+ / year to switch to pfSense+. The software only subscription is nearly 2x the cost of buying their entry level appliance (assuming a 5 year lifecycle). IMHO, that's an indicator they don't want to support 3rd party hardware and there's a risk they'll eventually drop it.

I wish VyOS had less crazy pricing because their stuff looks nice. They used to have a $600 / year professional subscription which they don't appear to offer anymore. I think the corporate subscription used to be <$4k / year and now it's $6k. I wonder why no one wants to commit to subscriptions. How can I sell anything to a customer when I can't give a predictable price for ongoing maintenance a year into the future?

Our customers will literally go back to using their ISP supplied modems instead of proper firewalls before they'll pay the prices everyone is asking for. I don't blame them either. They only need a fraction of the functionality being sold and all of the fancy, expensive features everyone is using to justify sky high pricing are simply bad value in that context because they'll basically unneeded bloat.

Re:Resolving an unusual WiFi issue by xoa on Friday August 19, 2022 @10:03PM (#32528333)
>Thanks for taking the time to reply.

No problem, glad to chat about this and commiserate a bit with someone in a similar boat.

>I've also soured on UniFi a lot over the last few years. It's crazy. The SMB / MSP market is massively underserved and instead of staying focused and capturing it Unifi is trying to compete in the enterprise market where, IMHO, they aren't going to succeed.

Yeah, it's such a huge waste. But the CEO is a classic trouble case with near total control (owns majority of the stock and thus effectively owns the board, a few caveats in terms of protection for minority shareholders in public companies don't really stop the trend).

>If we try out Omada and feel like it gives us everything Unifi does without all the feature creep then we'll do the same thing as you; EoL sites will move from Unifi to Omada. I'll always take fewer features and stability over continuous new features.

UniFi hasn't even had "continuous new features" though! Or rather, their "features" have been stuff like reskinning the GUI or doing their own entire custom silly speedtest stack for a while, not "features" like PPSK, or for that matter just having normal DHCP and DNS management! Or any sort of certificate management or customization, or, like, anything of substance. Or on hardware, they didn't even bother to upgrade their UniFi Security Gateways literally ever, not once! The ones still selling now are the exact same hardware as 2014 launch, no new updates in forever. They intro new stuff without ever sunsetting older stuff in general really. Use "EA" as a popularity poll test. The dysfunction goes on and on.

I don't know if Omada will be the answer yet but worth a spin IMO. I'd definitely hate having to either go back to lots of individual management or something cloud-based. I am stick with UI for PtP/PtMP stuff for the time being though, even if some rot is creeping in there too.

>We've used pfSense forever and have been happy with it. However, 2.6.0 has some gateway/dpinger issues where the bug fixes are slotted for 2.7.0 on the CE side, so it feels like the inevitable neglect of the CE version might be starting to kick in there.

I'm afraid that company has a history of scummy behavior too :(. I think OPNsense is just plain better but ymmv. FWIW, while it's OSS there is at least one company (Deciso) that does a "Business Edition" at a relatively sane rate (~$150/yr, less for a 3 year) with no hardware reqs (they sell hardware too but I don't suggest getting it) and does business support contracts as well. And Sunny Valley Networks does an interesting little layer 7 inspector that can plugin to it. It conversely might not be good enough for your needs either, but it's not crazy. And the free version is still quite solid. As I said in another comment the docs are pretty decent so might be worth giving them a glance and firing up a system in a VM.

At any rate my clients are happy now. And despite rough edges I'm grateful there are a number of essentially decent options available.

Re:Resolving an unusual WiFi issue by inferiorhuman on Friday August 19, 2022 @10:03PM (#32528329)

  But basically Ubiquiti has become a toxic dumpster fire of a company and their product lines (UniFi in particular) on a downward trajectory in terms of performance, features and stability for quite a while.
I can't remember a time when Ubiquiti wasn't a dumpster fire. They've always seemed like the MongoDB of network hardware. For basic stuff it was okay, but "advanced" features like RADIUS, hardware acceleration, etc. never worked well. Their stuff's worked okay enough for me in the past, but it's really flared up with Sonic's 10G gear.

  But it's very, very pleasant to have the full spectrum of quality PC hardware available, you can get far more power for less, and you're never stuck with a critical aspect. 
Gotta disagree here. I went with Ubiquiti because I wanted purpose built network hardware. COTS hardware tends to be more expensive and power hungry. I'm cautiously optimistic about the new Marvell (ex-Cavium) stuff but it sounds like Mikrotik is having a hell of a time with that too.

The big problem is that homelab/SOHO folks (myself included) don't want to pay the upfront cost of supporting or developing/testing modern hardware. At the price point Ubiquiti is targeting I think any entrant will be doomed to failure.

Re:Resolving an unusual WiFi issue by xoa on Friday August 19, 2022 @10:59PM (#32528612)
>I can't remember a time when Ubiquiti wasn't a dumpster fire.

4-6 years ago things still looked quite promising, high energy great community and forums (gone now), a basic but workable issue/feature tracker (gone), lots of clearly talented engineers who were responsive and right there (gone), etc. Very good price/performance, quality and so on particularly compared to other stuff of the time. There was a reason it got a lot of recommendations. That was certainly a while ago now though.

They've always seemed like the MongoDB of network hardware.

Eh. Though a grim bit of irony is how old a version of MongoDB they've stuck on too amongst other things.

>COTS hardware tends to be more expensive and power hungry

Not enough to me to matter I guess. For applications like this one can find solid low power hardware, Xeon-Ds for example, that consume tens of watts at max load and idle plenty low. Or truly embedded stuff a single digits. There are enormous floods of stuff available that is a few years old for dimes or even pennies on the dollar. I replaced all my USG-4Ps with a few years old Supermicro Xeon-D front-network port systems I got for around $350. An extra 20W 24/7/365 is something like $20-30/year, for a device this important that's well worth it to me. And there's no comparison, it's a slaughter. Real systems have actual BMC/IPMI which is super handy if things go wrong. The performance is just ludicrously higher. It's trivial to have more RAM, the system runs off of mirrored ZFS drives I can count on, it can do HA, etc etc. All the normal tools are available.

I'd even take an old Celeron or Atom system over a USG though. Even without going to second hand market, something like Protectli's basic J3060 based FW2B would still be better IMO and has a max power of 12W, fanless. "Purpose built network hardware" doesn't mean much, hardware vlan filtering or offload for CRC/LRO/TSO are something a decent NIC can do, or even plenty of built-in stuff.

Re:Resolving an unusual WiFi issue by inferiorhuman on Saturday August 20, 2022 @12:18AM (#32529036)
For COTS stuff you can go cheap or powerful, but I've not seen anything that comes close at the $50 price point that the ER-X (or Mikrotik equivalent) goes for. The Protectli stuff is larger because it's mostly a giant heat sink. Intel's just not at the right point on the price/performance curve for fanless, and it's all way more expensive. The four port ER-X uses, what, a 12W power supply? Give me something more pared down. I don't want SATA ports, an integrated GPU, WiFi, LTE, whatever. The new Cavium (now Marvell) ARM stuff is interesting, but unobtanium stateside. For reference I bought into the ER-X when I was dealing with a couple different locations and I even bought one to toy around with.

As for Ubiquiti, I remember them thumbing their noses at the GPL and introducing security bugs in u-boot or having no idea how to fix the issues with RADIUS. They had no clue how to work around Cavium bugs (or get support from Cavium). I remember a company that shipped products based on a lightly skinned Vyatta using an end-of-life'd version of Debian (note that Debian ended support specifically for MIPS). I remember a company that shipped products (ER-X, ER-L) that ran hot enough to reliably cook themselves. And, yeah, Mongo. It was just a mess top-to-bottom.

Re:Resolving an unusual WiFi issue by lostlogin on Saturday August 20, 2022 @01:41AM (#32529447)
> 4-6 years ago things still looked quite promising

This is very true. However if you bypass the Dream Machine and just use some other router or an EdgeRouter it’s ridiculously reliable in the home setting.

There are a heap of nice features in the UDM line, but wow does it need polish and stability.

My wifi is the best I’ve every used by a million miles, but the UDMP crashes and has weird behaviour that requires heroics to repair.

Re:Resolving an unusual WiFi issue by ehPReth on Saturday August 20, 2022 @03:40PM (#32534637)
After a firmware upgrade my UI switches have been dropping off the network randomly (doesn't respond to ping, ssh) and stops switching traffic! I have to hard reset the switch to get traffic flowing again.. turning off a lot of the features as their forum suggested seems to have mostly worked but I still have issues now and then. I have even downgraded a little too but, eh. I really regret buying them but I'm not too sure where else to go for switches that are.. not super complex to manage for everyone.
Re:Resolving an unusual WiFi issue by kerr23 on Friday August 19, 2022 @07:34PM (#32527400)
I did the same, originally planned on UniFi but since i couldn’t get any i tried Omada. It’s very nice, the only issue i’ve had is my mesh not connecting, but i solved that by reorienting the target AP and boosting the source APs radio. I think i have some tuning left though because my devices don’t switch APs as fast as i’d like.
Re:Resolving an unusual WiFi issue by mh- on Friday August 19, 2022 @04:10PM (#32525449)
Yes, generated by AT&T's wireless STBs (cable boxes) back around 2014-15. It was a nightmare to figure out, as I recall.
Re:Resolving an unusual WiFi issue by Abishek_Muthian on Saturday August 20, 2022 @10:24AM (#32532251)
Not ARP storms per se, But I've noticed new Apple devices don't like router forwarding port 53 to pihole, resulting in bonjour storm and crashing pihole instances(Loosing DNS for the entire network).
Re:Resolving an unusual WiFi issue by ungamed on Sunday August 21, 2022 @05:33AM (#32538619)
If you can crash dns this way, please report it, its worthwhile fixing.
Re:Resolving an unusual WiFi issue by Abishek_Muthian on Monday August 22, 2022 @02:15AM (#32547948)
I'll try, Didn't have good experience with my earlier bug reports to Apple and now I'm completely out of that ecosystem. In fact I found this issue when my guests have iOS devices.

Anyways here's the regex blacklist I use in PiHole to prevent Apple's reverse DNS spam -

  ^(?:(?:\d+\.)*\d+(?:-in\.addr\.arpa\.)?)$
Re:Resolving an unusual WiFi issue by neurostimulant on Friday August 19, 2022 @06:10PM (#32526585)
Not sure if it's something similar but I had issue where attempting to setup a wifi smart plug locked up the router for a minute (until the smart plug gave up trying to connect to the router). Wired ethernet still works but the routers show 100% cpu usage on its management interface and the 2.4ghz wifi stopped working (didn't check the 5ghz one). I didn't dig in more because my wife was in a zoom meeting.
Re:Resolving an unusual WiFi issue by dylan604 on Friday August 19, 2022 @04:20PM (#32525533)
That takes did you turn it off and on again to an entirely different level. What if we need to do this city wide?
Re:Resolving an unusual WiFi issue by wizofaus on Friday August 19, 2022 @04:29PM (#32525605)
That sounds like a good plot for a movie - the day we had to reboot the entire internet...
Re:Resolving an unusual WiFi issue by Lammy on Friday August 19, 2022 @04:54PM (#32525807)
"South Park already did it": https://en.wikipedia.org/wiki/Over_Logging
Re:Resolving an unusual WiFi issue by wizofaus on Friday August 19, 2022 @05:45PM (#32526342)
Hah, yeah I did originally think something along those lines, but I wonder if you could actually do it non-comedically (e.g. somehow every node connected to the internet has to all be switched off at the same time and restarted to restore connectivity). Most likely it's already been tried too I guess.
Re:Resolving an unusual WiFi issue by dylan604 on Friday August 19, 2022 @06:21PM (#32526710)
usually, it's a nefarious evil doer that is threatening this action in the movies vs we gotta reboot the city.

there's been reboot the sun plot. there's been reboot the earth's core plot. there's been reboot the machine running the city plot.

Re:Resolving an unusual WiFi issue by wizofaus on Friday August 19, 2022 @06:25PM (#32526743)
I was thinking more along the lines of a rogue self-replicating packet where every last instance of had to die before routers and switches etc. would start working again.
Re:Resolving an unusual WiFi issue by gnopgnip on Friday August 19, 2022 @07:23PM (#32527310)
Spanning tree protocol will prevent broadcast/arp storms by preventing loops