Date: Mon, 4 Jul 2022 11:25:26 -0700 From: bob prohaska <fbsd@www.zefox.net> To: Karl Denninger <karl@denninger.net> Cc: freebsd-arm@freebsd.org Subject: Re: 13.1R problems on Pi3 Message-ID: <20220704182526.GB1771@www.zefox.net> In-Reply-To: <7ce87eef-ded5-8b00-3f11-14407b8af78d@denninger.net> References: <20220704003639.GA1165@www.zefox.net> <8820A9EC-A25E-4D0A-9F8F-52114E58B66F@yahoo.com> <6c377413-9430-54d2-3f92-1215055ca30a@denninger.net> <20220704152834.GA1771@www.zefox.net> <7ce87eef-ded5-8b00-3f11-14407b8af78d@denninger.net>
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On Mon, Jul 04, 2022 at 12:17:15PM -0400, Karl Denninger wrote: > > On 7/4/2022 11:28, bob prohaska wrote: > > On Sun, Jul 03, 2022 at 10:36:35PM -0400, Karl Denninger wrote: > > > > Can any sense be made of the few ping responses obtained when ntp > > is coming up? It's looks as if something happens after ntp runs > > that blocks subsequent network traffic, but why starting an outbound > > ping should partly unblock things is obscure to me. > > Yes.?? The odds are reasonably high that there is confusion as to which MAC > address maps to which device.?? This implies there's a loop between the two > switches (e.g. there is more than one way for packets to get into and out of > each said switch to the other) or the two devices are claiming the same MAC > address and thus when each "speaks" and performs ARP it "grabs" the map > which works until the next one pipes up and it grabs it. > Looks like that's the problem. There's only one cable between switches, but here's what I get from ifconfig on each host: On the machine running 13.1-R attached to switch 2: bob@www:~ % ifconfig lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6> inet6 ::1 prefixlen 128 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 inet 127.0.0.1 netmask 0xff000000 groups: lo nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> ue0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=80009<RXCSUM,VLAN_MTU,LINKSTATE> >>>>>>> ether b8:27:eb:71:46:4e inet 50.1.20.28 netmask 0xffffff00 broadcast 50.1.20.255 media: Ethernet autoselect (100baseTX <full-duplex>) status: active nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> bob@www:~ % hostname www.zefox.org bob@www:~ % bob@www:~ % uname -a FreeBSD www.zefox.org 13.1-RELEASE FreeBSD 13.1-RELEASE releng/13.1-n250148-fc952ac2212 GENERIC arm64 bob@www:~ % On the machine running an updated stable/13 system attached to switch 1: bob@pelorus:~ % ifconfig lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6> inet6 ::1 prefixlen 128 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 inet 127.0.0.1 netmask 0xff000000 groups: lo nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> ue0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=80009<RXCSUM,VLAN_MTU,LINKSTATE> >>>>>> ether b8:27:eb:71:46:4e inet 50.1.20.24 netmask 0xffffff00 broadcast 50.1.20.255 media: Ethernet autoselect (100baseTX <full-duplex>) status: active nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> bob@pelorus:~ % hostname pelorus.zefox.org bob@pelorus:~ % bob@pelorus:~ % uname -a FreeBSD pelorus.zefox.org 13.1-STABLE FreeBSD 13.1-STABLE #6 stable/13-n251601-2353343b324: Sun Jul 3 21:43:04 PDT 2022 bob@pelorus.zefox.org:/usr/obj/usr/src/arm64.aarch64/sys/GENERIC arm64 Thinking it over, I added the extra switch some time ago and didn't immediately notice any problems. Both Pi3s started out on the first switch (NetGear), with no obvdious problems. Later I probably moved one Pi3 to the second switch (D-Link) and started to notice troubles. Does this story make sense? > Each interface device from the factory is supposed to have a unique MAC > address.?? This can, for most interfaces, be overridden (modern Android > phones "randomize" it if told to as a "security" measure) but for obvious > reasons doing that can lead to problems. Collisions where multiple devices > are using the same MAC will lead to exactly the sort of thing you're seeing > because the switch is sending the packets to the wrong place. > > I've got a decent number of Pis of everything back to the "2" here and most > of the time several of them are on my network at once.?? I've not seen this > problem but I wouldn't exclude that both are claiming the same MAC and, if > so, that's what's causing the problem. > [example ifconfig output snipped] > > That MUST be unique on your LAN; the prefix (first three octets) is a vendor > code /*and the last three should never be duplicated by a vendor. */If you > are not setting it in /etc/rc.conf or elsewhere and there /are /duplicates > then a very bad thing happened when those units were manufactured -- set one > of them to something else. > Any pointers to MAC-setting methods appreciated..... Thanks very much for writing! bob prohaska
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