@Jeff,

Thank you for the detailed explanation and for sharing your solution. It’s indeed common for firewall rules to block SMB traffic, especially if the server is configured with strict security settings.

Your use of nmap to diagnose the issue is a great approach, as it can help identify which ports are open and which are being blocked.

To definitively diagnose the issue, run the nmap command (you may have to install nmap) as root:

$ sudo nmap -sT -p 135:139,445 SERVER-NAME
or
$ sudo nmap -sT -p 135:139,445 SERVER-ADDRESS

I then fixed the problem by adding rules to the iptables, chain INPUT with commands **similar** to:

# iptables -I INPUT  -s 192.168.0.0/24 -p tcp -m tcp  --sport 135:139 -j ACCEPT
# iptables -I INPUT -s 192.168.0.0/24 -p tcp -m tcp --dport 443 -j ACCEPT
# iptables -I INPUT  -s 192.168.0.0/24 -p udp -m udp  --sport 135:139 -j ACCEPT
# iptables -I INPUT -s 192.168.0.0/24 -p udp -m udp --dport 443 -j ACCEPT

I’m running off of ancient memory if the udp rules are required or not and I don’t have time to test that right now. This works and for the moment, that’s good enough for me.

This is going on somewhat outdated information, it may be that the…

@Nuno,
You’re helpful as always. Thanks for bringing that to our attention.

A command That I think that will be useful in this article is the showmount command to search for available NFS shares on a remote server.

A simple example like run ‘showmount -e 192.168.0.10’ to view all NFS shares available on 192.168.0.10, will be great.

Best,
Nuno

@Gabriel,

Corrected in the writeup as suggested by @Eugene.