Date: Wed, 28 Oct 2020 15:27:52 +0100 From: Michael Gmelin <freebsd@grem.de> To: D'Arcy Cain <darcy@druid.net> Cc: FreeBSD Net <freebsd-net@freebsd.org> Subject: Re: Bridge woes Message-ID: <FCCDA085-300D-4465-BFD2-45F11C59D3EF@grem.de> In-Reply-To: <6ca8956a-76d0-8d83-e1ce-015de1fcf2bd@druid.net> References: <6ca8956a-76d0-8d83-e1ce-015de1fcf2bd@druid.net>
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> On 28. Oct 2020, at 12:32, D'Arcy Cain <darcy@druid.net> wrote: > > On 10/27/20 2:58 PM, Michael Gmelin wrote: > > I hope you don't mind but I reverted this conversation back to the list in case it gives someone else any ideas. > >> Hi, >> I tried to reproduce the problem on my home network, but things just >> work as expected. >> I could run VMs with IPs off the local network, fixed ones as well as >> DHCP. >> The topology looks a bit different: >> vm->server->router ->(nat)-> internet >> | >> + dhcp/dns > > I suppose that that is essentially the same but let me see if I get it. You have a network, say 192.168.1.0/24, behind your NAT router. You have physical servers like 192.168.1.1 and 192.168.1.2 on this network. You then put a VM on the .1 host numbered 192.168.1.3 and it can connect to 192.168.1.2. Is that correct? > >> I would speculate that there's either something going on with >> the switch (you might want to take a look at it), or you're experiencing >> some sort of asymmetric routing issue (ping/icmp is usually just fine > > Not sure what that could be. It's not just a problem with external hosts. Hosts on the same network are also showing the symptoms. Another point is that I can access it inbound. It's only outbound connections that don't work. > >> with that). Or it might be something with the bge driver (I'm using em > > The only server that it can connect to is running bce. I have some em servers but it doesn't connect to those. > >> here). I assume you already tried disabling all sorts of offloading to >> see if it makes a difference? > > Yep. I tried -tso -lro -rxcsum -rxcsum6 -txcsum -txcsum6 -vlanhwtag -vlanhwtso and subsets of that. > >> Other than that I would suggest to play with tcpdump to see if packets >> are returned on the same interface they've been sent out on or not. > > Here is an example packet seen on the host: > > 11:20:40.397067 IP 98.158.139.71.44448 > 98.158.139.66.22: Flags [S], seq 3285763868, win 65535, options [mss 1460,nop,wscale 6,sackOK,TS val 3003762262 ecr 0], length 0 > > The .66 never sees the packet and the host never sees a return packet. On the other hand, a connection attempt from .66 to the VM shows up properly. > > >> Proxy arp might play a role on a local network, that's something I've >> seen in the past when I has hosts with multiple interfaces on the same >> (multiple) networks. If you can afford to try it, I would see if >> shutting down eth1 (and then flushing all arp tables on all >> hosts/devices involved in your test) makes a difference[0]. > > I want to be careful about dropping eth1 as it is the only way in if I mess up eth0. > Can you (afford to) reboot the machine reliably? If so, schedule a reboot using "shutdown -r +10" and then bring down the the interface to see if it makes a difference. -m > -- > D'Arcy J.M. Cain <darcy@druid.net> | Democracy is three wolves > http://www.druid.net/darcy/ | and a sheep voting on > +1 416 788 2246 (DoD#0082) (eNTP) | what's for dinner. > IM: darcy@VybeNetworks.com, VoIP: sip:darcy@druid.net > > Disclaimer: By sending an email to ANY of my addresses you > are agreeing that: > > 1. I am by definition, "the intended recipient". > 2. All information in the email is mine to do with as I see > fit and make such financial profit, political mileage, or > good joke as it lends itself to. In particular, I may quote > it where I please. > 3. I may take the contents as representing the views of > your company if I so wish. > 4. This overrides any disclaimer or statement of > confidentiality that may be included or implied in > your message.
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