Port 25 not connecting

[Keith Miller]

I have installed a VM (Ubuntu 18.04) with no firewall installed either with Ubuntu or Proxmox, but port 25 will not connect, I have checked it with a off site utility and by trying to telnet net into it and nmap also show it not listening

en04 is configured for connecting through a bridged port on my modem and vmbr4 is connected to eno4 both have no network info entered
web site communicates fine but just no connection on port 25

Thanks for help

 

[Stoiko Ivanov]

Can you connect to port 25 from the PVE-host (just temporary configure an ip in the same network where the Ubuntu VM has its service listening on port 25) ?

Can you connect to port 25 from another device behind the modem (i.e. in the same network as the Ubuntu VM)?

Some ISPs block in-/ outbound port 25 to prevent SPAM originating from their network - contact your ISPs support

I hope this helps!

 

[Keith Miller]

Can you connect to port 25 from the PVE-host (just temporary configure an ip in the same network where the Ubuntu VM has its service listening on port 25) ?

Can you connect to port 25 from another device behind the modem (i.e. in the same network as the Ubuntu VM)?

Some ISPs block in-/ outbound port 25 to prevent SPAM originating from their network - contact your ISPs support

I hope this helps!

I tried connect from a another VM and got unable to connect to remote host : connection was refused

I can not connect to it from a workstation behind the modem

I have a business account and they do not block port, talked to them yesterday

 

[Stoiko Ivanov]

Does the service listen inside the Ubuntu VM ? (run `ss -tlnp` inside and check for something listening on port 25)
Are you sure that there is no firewall in place? ( check with `iptables -nvL` on PVE and inside the VM)

 

[Keith Miller]

looks like it's listening, not sure does the results of firewall tell you there is one installed, if it does I did not install it

 

[Stoiko Ivanov]

The services are listening only on localhost (127.0.0.1) - and nothing is listening on a reachable IP of the VM -> check how to configure the software to listen for connections from the outside

I hope this helps

 

[Keith Miller]

are you saying there is a firewall installed

I will google the heck out of it

thanks

 

[Stoiko Ivanov]

No - sorry I was not clear enough:
* the iptables output indicates that there are no rules configured (i.e. no firewall installed)
* I was referring to the screenshot of the `ss -tlnp` output:
the line with `127.0.0.1:25` shows that whatever is listening on port 25 is only listening on '127.0.0.1' (a.k.a localhost a.k.a the loopback interface) - this means you cannot connect from the outside.

You need to change the configuration of the software which should be running on port 25 to bind to '0.0.0.0' instead

I hope this explains it!

 

[Keith Miller]

Yes thank you for clarifying that, I'll keep Googleing on how to do that