Alfresco and CIFS troubleshooting on Ubuntu

When installing Alfresco on an Ubuntu machine, CIFS doesn’t work out of the box.
First question: is Samba installed?
sudo apt-get install samba smbfs

The configuration files for file-server setups:
$ALFRESCO_HOME/tomcat/webapps/alfresco/WEB-INF/classes/alfresco/file-servers.xml
$ALFRESCO_HOME/tomcat/webapps/alfresco/WEB-INF/classes/alfresco/file-servers.properties

Uncomment these lines in file-servers.xml (though to make sure this is permanent – create file-servers-custom.xml):
<tcpipSMB port="1445" ipv6="${cifs.ipv6}" platforms="linux,solaris,macosx"/>
<netBIOSSMB sessionPort="1139" namePort="1137" datagramPort="1138" platforms="linux,solaris,macosx"/>

Set iptable rules:
sudo su
echo 1 > /proc/sys/net/ipv4/ip_forward
modprobe iptable_nat
iptables -F
iptables -t nat -F
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
iptables -t nat -A PREROUTING -p tcp --dport 445 -j REDIRECT --to-ports 1445
iptables -t nat -A PREROUTING -p tcp --dport 139 -j REDIRECT --to-ports 1139
iptables -t nat -A PREROUTING -p udp --dport 137 -j REDIRECT --to-ports 1137
iptables -t nat -A PREROUTING -p udp --dport 138 -j REDIRECT --to-ports 1138

Check iptable rules:
sudo iptables -t nat -L

Troubleshooting options:
To check what ports are listened to:
netstat -a
Look for:
tcp6 0 0 [::]:1445 [::]:* LISTEN
tcp6 0 0 [::]:1139 [::]:* LISTEN

To see who listens at what port:
$ sudo lsof -i :1139 -n
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
java 11881 alfresco 296u IPv6 60400 TCP *:1139 (LISTEN)

Another way to check if the port is listened to:
$ telnet localhost 1139
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

Resources:
http://wiki.alfresco.com/wiki/File_Server_Configuration
CIFS Linux
http://wiki.alfresco.com/wiki/Troubleshooting
CIFS Troubleshooting