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myitcv
Contributor
Contributor

Debian network drops

Hi all - I have, thanks to https://twitter.com/mitchellh/status/1560313710324789248, managed to get full 3D acceleration within a new Debian bookworm VM. This required me to upgrade from my existing Ubuntu setup (at some point I will switch to nixOS) to Debian (using the v5.19 kernel and a rebuilt version of mesa to include svga drivers).

The transition to debian has been seamless, but for one thing.

After a period of inactivity, my Debian guest loses network access. My rather crude fix for this is a reboot. But I'm sure a) this shouldn't happen, and b) there is probably a better workaround to "fix" things in the immediate term.

I've googled/searched with various terms but to no avail. 

I would be very grateful of any pointers! 

Thanks in advance.

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Technogeezer
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Immortal

NAT or Bridged networking?


There’s a known issue with both the Tech Preview and the released Fusion 12 with NAT networking where it will drop out unexpectedly. Try switching to bridged networking and see if that helps if you are indeed running NAT networking. 

- Paul (Technogeezer)
Editor of the Unofficial Fusion Companion Guides
myitcv
Contributor
Contributor

Thanks very much, @Technogeezer! Will give that a try

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myitcv
Contributor
Contributor

Unfortunately this does not work, reliably at least.

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myitcv
Contributor
Contributor

I've been running into this a lot more over the last couple of days. Two things I've discovered:

1. I can restore the network relatively easily by running ifdown on the network interface, followed by ifup. Ideally I wouldn't have to do this, but I've stuck the command behind an alias and it's easy to recover.

2. This happened again ~5 mins ago and so I quickly looked at the logs in /var/log/syslog:

$ sudo grep -i dhcp /var/log/syslog | tail -n -15
2023-03-31T23:37:57.935104+01:00 debian dhclient[742]: DHCPOFFER of 192.168.223.134 from 192.168.223.254
2023-03-31T23:37:57.935197+01:00 debian sh[742]: DHCPOFFER of 192.168.223.134 from 192.168.223.254
2023-03-31T23:37:57.935214+01:00 debian sh[742]: DHCPREQUEST for 192.168.223.134 on ens160 to 255.255.255.255 port 67
2023-03-31T23:37:57.935233+01:00 debian dhclient[742]: DHCPREQUEST for 192.168.223.134 on ens160 to 255.255.255.255 port 67
2023-03-31T23:37:57.937861+01:00 debian dhclient[742]: DHCPACK of 192.168.223.134 from 192.168.223.254
2023-03-31T23:37:57.937930+01:00 debian sh[742]: DHCPACK of 192.168.223.134 from 192.168.223.254
2023-03-31T23:15:23.305328+01:00 debian dhclient[21603]: Internet Systems Consortium DHCP Client 4.4.3-P1
2023-03-31T23:15:23.306774+01:00 debian dhclient[21603]: For info, please visit https://www.isc.org/software/dhcp/
2023-03-31T23:15:23.335276+01:00 debian dhclient[21603]: DHCPRELEASE of 192.168.223.134 on ens160 to 192.168.223.254 port 67
2023-03-31T23:15:23.461183+01:00 debian dhclient[21624]: Internet Systems Consortium DHCP Client 4.4.3-P1
2023-03-31T23:15:23.461496+01:00 debian dhclient[21624]: For info, please visit https://www.isc.org/software/dhcp/
2023-03-31T23:15:23.558525+01:00 debian dhclient[21624]: DHCPDISCOVER on ens160 to 255.255.255.255 port 67 interval 4
2023-03-31T23:15:24.562173+01:00 debian dhclient[21624]: DHCPOFFER of 192.168.223.134 from 192.168.223.254
2023-03-31T23:15:24.562787+01:00 debian dhclient[21624]: DHCPREQUEST for 192.168.223.134 on ens160 to 255.255.255.255 port 67
2023-03-31T23:15:24.564443+01:00 debian dhclient[21624]: DHCPACK of 192.168.223.134 from 192.168.223.254

Look closely at the times. The time jumps _backwards_ from 23:37 to 23:15.

This has to be related, because the network dropped at almost exactly the time the system clock changed.

Does this correlate with what others are seeing?

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Technogeezer
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Time jumping backward makes me wonder if you have both time sync with the Mac enabled in the VM's preference and Automatic Date & Time enabled in the Date&Time settings within the VM.  Dueling time sync is not considered a good idea. You should be using one or the other.

It wouldn't surprise me if the DHCP lease is getting confused by the backward time change of a fairly large delta (almost 17 minutes). Are there any items in the VM's system logs indicating what might be moving the clock back? 

Please note that this forum isn't really active any more since the release of Fusion 13. You'll get more views if you post in the "production" VMware Fusion forum. You can add a link back to this forum if you need to reference the information in it.

 

- Paul (Technogeezer)
Editor of the Unofficial Fusion Companion Guides
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