From VM unable to connect to service in LAN

Apps and Virtualization
1

Hello,

I have a very strange one that has me stumped for a number of days.

Situation:

Truenas Scale 24.04.2 using bridge network connected to managed switch. Another device is setup and connected to the same lan on the same switch.
Management device is also connected to the same switch.

Problem:

I am unable to connect to any service on any server that is not hosted on the TrueNAS.

I can ping any device on the lan. I can connect to any VM running on the TrueNAS, I can even make a telnet connection to any website outside my LAN. I am unable to connect to any other service then a ICMP on the lan.

From the lan I am able to connect to any VM/service that is running. Just from the VM itself it is just not possible.

When doing a tcpdump, I noticed that the initial packet is re-transmitted. And when I try to do a ‘telnet vm-host 443’ it works, when I do the same for any public site it works. Just trying to connect to any service on the LAN that is not hosted on the TrueNAS, it just fails.

Any ideas what I can do to fix this?

2

For me the fix was moving away from TrueNAS to Proxmox.

3

I’m not sure that is a fix… are you still looking to find the issue or have to just changed platforms and no longer have the issue to resolve.

4

Well, I wanted to figure out what the problem was, however after spending more the 24h on it. To no avail. The move to a different platform was the best for me.

The issue is very strange. Being able to send out ICMP packets but normal SYN packets are being retransmitted.

I agree it is not really a fix. But for me moving platforms was the best.