Re: [gentoo-user] Two wifi client interfaces and routing
Thanks for the detailed reply - my response is inline: On 1/4/22 00:17, Grant Taylor wrote: > On 3/31/22 7:21 AM, William Kenworthy wrote: >> Hi, > > Hi, > >> I am trying to use a raspberry pi ... to create a routed link >> between two access points ... so I can access the monitoring port >> ... from homeassistant. > > I'm distilling this down to a Gentoo system participating in two two > LANs, both of which are connected as DHCP clients. -- Correct me if > I've distilled too much. -- And you want other systems on either LAN > to use this system as a communications path to systems on the opposing > LAN. > Correct, though I only need systems on the home network side (from at least two VLANs) to access through the rpi - this device, as well as some other "untrusted", cloud devices are on their own VLAN) - the inverter is an island and I need to access just that one port. >> Both AP's connect ok from the rpi but the routing is wrong - I can >> ping in both directions from the rpi, but only sometimes from devices >> further hops away - can openrc even do this? > > This seems like a classic routing issue. To me, it's not even an > OpenRC issue in any way other than how to add static routes /after/ > the network is brought up via DHCP. Agree - I would describe it as a two gateway and related routing issues with something resetting/re-configuring of the routing tables into a nonsensical state when I try and manually manipulate them. I did forget to mention I use ospfd (frr) to propagate routes (a complex, multi VLAN network) which works fine - its openrc setting the wrong routes on the rpi which then get propagated - thats not central to this issue though. > >> My experimenting so far is hit and miss. Trying to static route or >> override the default routes doesn't survive a network glitch, and >> half the time doesn't seem to "take" at all. > > Ya. At a higher level, this can be non-obvious how to do this as it's > niche routing configuration. > >> A working example I could adapt would be great! > > I don't have an example off hand. -- Seeing as I use static IPs on > almost all of my machines, I don't even know if OpenRC supports adding > a static route /after/ bringing an interface up with DHCP. It does, but its either set the network configuration manually which kept getting extra routes added - in particular the inverter sends the gateway which dhcpd adds then I have to delete ... and gets undone at the next network glitch (hostile wifi environment plus weak signal). > > I do know that the DHCP protocol supports adding additional options / > definitions / parameters (?term?) to specify -- what I've been > describing as -- static routes. That way DHCP clients will learn > about these additional routes and install them in their local routing > table. Though I don't know if you will have the necessary control over > /both/ DHCP servers that's needed to do this. Unfortunately, the inverter is a black box :( > > Presuming that you don't have control over /both/ DHCP servers (as > control over /both/ will be needed), I'm going to fall back and > suggest what I call the "Customer Interface Router". I cant control the inverter network. > > Specifically, set up port forwarding on the Pi such that when clients > on LAN1 connect to $PORT on the Pi, the traffic is DNATed to the > HomeAssistant on LAN2 /and/ the traffic is SNATed to the LAN2 > interface on the Pi. Thus every system on each LAN thinks that it's > talking to a directly attached system in the same LAN. There is no > need for routing in this case. I have not tried this as I thought it would also run into the two default gateway issue ... I'll try this next! > > I typically only use the C.I.R. when there are reasons that more > proper routing can't be configured. The C.I.R. is an abstraction > layer that allows either side to operate almost completely > independently of each other, save for IP conflicts between each > directly attached LAN. I have now been given api credentials but they don't say if it runs on the inverter or a remote site ... more reading! At this stage all I need is simple monitoring that I can process using software. Thanks, BillK > > >
Re: [gentoo-user] Two wifi client interfaces and routing
On 3/31/22 10:17 AM, Grant Taylor wrote:
I do know that the DHCP protocol supports adding additional options /
definitions / parameters (?term?) to specify ... static routes.
In case others are interested in this, a few pointers about using it.
ISC's DHCP server has two options for advertising routes that clients
should install;
subnet ... netmask ... {
...
option cidr-static-route ...;
...
ms-static-route ...;
...
}
Both *-static-route options use the same format and the format took a
little bit to wrap my head around. It consists of sets of length>, followed by the , followed by the router. E.g.
option cidr-static-route 10, 100, 64, 192, 0, 2, 123, 0, 192, 0, 2, 1;
That says:
- 100.64.0.0/10 is reachable via 192.0.2.123
- 0/0 is reachable via 192.0.2.1
ProTip: Go ahead and add the default gateway 0/0 route to the
*-static-route entries as some clients ignore the option routers entry
when *-static-route option is present.
I have multiple macOS, iOS, Windows 10, Linux, and other esoteric things
correctly using a route to a lab / sandbox subnet via a system that
isn't the LAN's default gateway.
Finally: This seems to be a well defined DHCP standard, but seemingly
not well known option by the various people that I've discussed this with.
--
Grant. . . .
unix || die
Re: [gentoo-user] Two wifi client interfaces and routing
On 3/31/22 7:21 AM, William Kenworthy wrote: Hi, Hi, I am trying to use a raspberry pi ... to create a routed link between two access points ... so I can access the monitoring port ... from homeassistant. I'm distilling this down to a Gentoo system participating in two two LANs, both of which are connected as DHCP clients. -- Correct me if I've distilled too much. -- And you want other systems on either LAN to use this system as a communications path to systems on the opposing LAN. Both AP's connect ok from the rpi but the routing is wrong - I can ping in both directions from the rpi, but only sometimes from devices further hops away - can openrc even do this? This seems like a classic routing issue. To me, it's not even an OpenRC issue in any way other than how to add static routes /after/ the network is brought up via DHCP. My experimenting so far is hit and miss. Trying to static route or override the default routes doesn't survive a network glitch, and half the time doesn't seem to "take" at all. Ya. At a higher level, this can be non-obvious how to do this as it's niche routing configuration. A working example I could adapt would be great! I don't have an example off hand. -- Seeing as I use static IPs on almost all of my machines, I don't even know if OpenRC supports adding a static route /after/ bringing an interface up with DHCP. I do know that the DHCP protocol supports adding additional options / definitions / parameters (?term?) to specify -- what I've been describing as -- static routes. That way DHCP clients will learn about these additional routes and install them in their local routing table. Though I don't know if you will have the necessary control over /both/ DHCP servers that's needed to do this. Presuming that you don't have control over /both/ DHCP servers (as control over /both/ will be needed), I'm going to fall back and suggest what I call the "Customer Interface Router". Specifically, set up port forwarding on the Pi such that when clients on LAN1 connect to $PORT on the Pi, the traffic is DNATed to the HomeAssistant on LAN2 /and/ the traffic is SNATed to the LAN2 interface on the Pi. Thus every system on each LAN thinks that it's talking to a directly attached system in the same LAN. There is no need for routing in this case. I typically only use the C.I.R. when there are reasons that more proper routing can't be configured. The C.I.R. is an abstraction layer that allows either side to operate almost completely independently of each other, save for IP conflicts between each directly attached LAN. -- Grant. . . . unix || die
[gentoo-user] Two wifi client interfaces and routing
Hi, I am trying to use a raspberry pi (3B running gentoo 32bit, openrc) to create a routed link between two access points (the rpi acting as a client to both AP's) so I can access the monitoring port (6607, modbus) from homeassistant. One AP is an Huawei inverter with a built in "island" access point that sets a default route to itself on clients via dhcp. I have a normal gentoo based Access Point for the house that also sets a default route via dhcp. What I need is a single default route to my home network via the rpi from the Huawei inverter. Both AP's connect ok from the rpi but the routing is wrong - I can ping in both directions from the rpi, but only sometimes from devices further hops away - can openrc even do this? My experimenting so far is hit and miss. Trying to static route or override the default routes doesn't survive a network glitch, and half the time doesn't seem to "take" at all. A working example I could adapt would be great! BillK
