Hopefully, this belongs in network connectivity as I suspect the resolution might lie somewhere other than just with Hamachi.

The Raspberry Pi 1B I was using as a Logmein Hamachi gateway died the other day and I'm trying to replace it a Raspberry Pi 3B+ that I built with full version of Rasbian (based on Debian Buster).

I manually configured ethernet and switched of WiFi. Ethernet is configured with a static IP address 192.168.x.x/24 with my router set as the default gateway and with my network DNS server set as the default with Google's 8.8.8.8 as a secondary. IPV6 is disabled. Everything worked. I enabled SSH on the Pi and checked I could remotely log in.

I installed Hamachi thus:Then configured it with:I did the above on the 'other machine' via SSH. However, a few minutes after the above, I lost SSH connectivity to the Pi. Returning to the local console on the Pi, I note that all the expected interfaces are up (eth0 and the three associated with hamachi). Pi config shows SSH is still enabled. However, I can't ping or traceroute to external resources (like bbc.co.uk). Doing $ sudo service ssh status shows that ssh is running.

Doing $ sudo dpkg -r logmein-hamachi restores SSH and other networking connectivity. FWIW, this is the second attempt at building this Pi and I had a similar issue with XRDP at the first attempt.

Help! All assistance to sort out this conflict will be gratefully received.

Can you ping an IP address, like 8.8.8.8?

What's the output of ip route?

I can't ping any external resources (e.g. 8.8.8.8), for that I can't even ping the default router.

I don't like posting my network specifics, but I can't see a way out of it here, so output of ip route follows:
I've just noticed that ham-br0 appears to be set via DHCP and also there are two entries for my local network (192.168.42.0) but I thought that the lowest metric would be the default.

Does this give a clue?

Thanks, Geoff

You have the same network (192.168.42.0/24) on two different interfaces. That's not a valid IP configuration.

What does brctl show ham-br0 have to say about the bridge? If eth0 is connected to ham-br0 (which it seems to be), eth0 shouldn't have an IP address at all.

Thanks. I don't seem to have brctl available. Do I need to install a package to get this or is there another way to get the info you asked for?

FWIW, eth0 needs an IP address otherwise the Pi won't be able to access stuff on my local network?

Edited to add: Searching the 'net shows that brctl is part of the bridge-utils package -- but I can't install it because of the network issue I'm trying to resolve!

D'Oh! back to basics ... downloaded the .deb package and copied to the Pi via sneaker mail and installed using dpkg.

brctl shows eth0 and ham1 as the interfaces. I suspect it should be ham0 and ham1 but I've no idea how to confirm this or how to change it!

Thanks again, Geoff

I know Debian has this in bridge-utils.
Not if it's connected to a bridge. The IP address should then be moved to the bridge interface.

If this is indeed the reason you're losing network connectivity, ip addr del 192.168.42.127 dev eth0 should make things work again (temporarily, at least), and you should be able to SSH into the box via the address assigned to the bridge.

Thanks again. That said, I suspect I won't be able to SSH onto the box with the IP addr of eth0 deleted as the machine I'm trying to connect from is on the 192.168.42.0/24 network. I don't mind trying, but not until I know how to reverse the deletion (ip addr add 192.168.42.127 dev eth0?) Or am I missing something?

According to your earlier posts, the ham-br0 bridge also has an IP address in the 192.168.42.0/24 network. Try SSHing to that once the address on eth0 is removed.

Adding an IP address requires the CIDR mask to be specified: ip addr add 192.168.48.127/24 dev eth0.

Actually, you should include the CIDR mask when deleting an address as well. Leaving out the mask may still work depending on your version of ip, but it's deprecated and not good practice in any case.

Thanks again. I deleted IP address 192.168.42.127 but to no avail. The system seems to have automatically restored it (probably from one or more configuration files?). Still can't ping out even to the local router or to 8.8.8.8 and can't SSH into the bridge local IP address.

Sorry to reply to my last post. Further research suggests that the Pi 3B+ is prone to networking issues and so I've decided to abandon trying to use the Pi as a Hamachi gateway, which is a pity as the now dead Pi 1B worked flawlessly with the early version of Hamachi installed back in 2013. I have an old Gigabyte mini-ITX machine that I resurrected by building with Debian 10 and then installed the current Hamachi i386 .deb via dpkg. This worked without issues. However, I'll have to live with the additional power consumption...

Thanks Ser Olmy for trying, much appreciated.

Edited to add:
It turns out that Raspbian Buster has problems with Hamachi v2 armhf and that installing the last version of Raspbian Stretch (i.e. based on Debian Stretch) resolved the issue. I can confirm that the Hamachi works on my Pi 3B+ under Stretch. My thanks to the guys over on the Hamachi Community Forum.