ShareFS - what's needed to make it work?

I only just started to try RPCEmu a few days ago. I see from its docs that ShareFS doesn’t work.

What would be necessary to make it work?

I talked to the maintainers at the show about this – it is a problem they are well aware of, associated with enabling ShareFS to work through the NAT translations. I understand that the recent networking changes are a small step towards a solution, but still a lot more work to do. However, there may not be any reasonable solution.

Thank you, Martin. I confess I was hoping for more specifics in the reply.

Is broadcast part of the problem?

Is broadcast part of the problem?

Quite likely to be most of the problem – as in the networking setup being a NAT Virtual router, and broadcasts don’t route.
There are methods to forward broadcasts, but generally speaking the received wisdom is that forwarding anything other than DHCP broadcasts is bordering on insanity on both security and network traffic grounds.

For this specific use case, I suspect the most sensible course would be to change ShareFS to use something routable which is not a quick and easy task.

generally speaking the received wisdom is that forwarding anything other than DHCP broadcasts is bordering on insanity on both security and network traffic grounds.

ShareFS already uses broadcast, so if it were a real problem, no-one would be able to use ShareFS.

IIUC only four ports need to be open for receipt of broadcast traffic, and then only from the LAN – I don’t think anyone would suggest opening it up to the wider world. That would be bordering on insanity, I agree.

I suspect the most sensible course would be to change ShareFS to use something routable

Then it wouldn’t be ShareFS. It wouldn’t be compatible with anything out there.

I did suggest a few years back that a ShareFS 2 would be a good idea, taking the best ideas from ShareFS and replacing the problematic bits. Vague, I know. One of the problems we’re suffering from is the absence of source code for ShareFS.

I see I should have read the RPCEmu networking instructions more extensively and carefully. It does look like it’s possible to get ShareFS working, but it’s more involved to set it up to do so.

It does look like it’s possible to get ShareFS working, but it’s more involved to set it up to do so.

Hmm!! This is from the Release notes

Network Address Translation

For the amount of effort it’d need to set up iptables etc.¹ I’m sure it’d be more productive in the long run to simply set up a share either on the system RPCEmu is running on – even if it’s outside the RPCEmu dir, symlink it – or on a server visible to both!

¹ I have a feeling I got it working a few years back, but all my RPCEmu networking is in bridged mode on Linux hosts.

In my experience, ethernet bridging supports ShareFS (though I admit it’s been a while since I used it…). Piece of cake to set up if your host is Linux and it’s in a LAN. Just install bridge-utils, get rid of network-manager and create /etc/network/interfaces, looking something like this:

(had to remove the comments because the retarded forum software screwed them up even in a pre and/or code section…).

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual
 
auto br0
iface br0 inet static
    address 192.168.1.2
    network 192.168.1.0
    netmask 255.255.255.0
    gateway 192.168.1.1
    broadcast 192.168.1.255
    bridge_ports eth0
    bridge_fd 9
    bridge_hello 2
    bridge_maxage 12
    bridge_stp off
    bridge_hw xx:xx:xx:xx:xx:xx

Some of that may be obsolete (this file is from 2013 and I think the netmask setting isn’t set like that anymore, but hey, this still works here).
The bridge_hw (actually a mac address) bit was added later when systemd’s networkd junk started messing with the settings. It may not be necessary on your system.

In the above, 192.168.1.2 is the host’s address. Give your other machines on the LAN – including RPCEmu – whatever address you like between 192.168.1.3 and 192.168.1.254.

[yes, I’m back already – too curious to stay away…]

ShareFS already uses broadcast, so if it were a real problem, no-one would be able to use ShareFS.

In the same network segment it isn’t a problem, however broadcasts do not route and the RPCEmu NAT setup is a NAT router.

If you use a bridging config then it may be possible, what it takes in alteration of RPCEmu to do that is unknown

Bridging setup is host only. No changes necessary in RPCEmu. Just set it up normally (manual address).