What ports need to be open for Samba to communicate with other windows/linux systems? I need to configure Linux firewall so I need the exact port TCP and UDP port numbers for SMB/CIFS networking protocol.
You can get list of ports from file called /etc/services. For your ease of use here are ports you need to open for two-way samba communication with Windows and Linux desktop systems.
- netbios-ns - 137/tcp # NETBIOS Name Service
- netbios-dgm - 138/tcp # NETBIOS Datagram Service
- netbios-ssn - 139/tcp # NETBIOS session service
- microsoft-ds - 445/tcp # if you are using Active Directory
Other ports:
- Port 389 (TCP) - for LDAP (Active Directory Mode)
- Port 445 (TCP) - NetBIOS was moved to 445 after 2000 and beyond, (CIFS)
- Port 901 (TCP) - for SWAT service (not related to client communication)
Command To Find Out Required TCP/UDP Ports For SMB/CIFS Networking Protocol
Type the following command:
$ grep -i NETBIOS /etc/services
Sample outputs:
netbios-ns 137/tcp # NETBIOS Name Service netbios-ns 137/udp netbios-dgm 138/tcp # NETBIOS Datagram Service netbios-dgm 138/udp netbios-ssn 139/tcp # NETBIOS session service netbios-ssn 139/udp
Sample iptables Rules
To open Samba communication between 192.168.1.0/24 subnet representing the machines on your network which should operate as clients of the Samba server. Edit /etc/sysconfig/iptables under RHEL/CentOS server. Add the following lines, before the final LOG and ROP lines for the RH-Firewall-1-INPUT chain:
-A RH-Firewall-1-INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 137 -j ACCEPT -A RH-Firewall-1-INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 138 -j ACCEPT -A RH-Firewall-1-INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 139 -j ACCEPT -A RH-Firewall-1-INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 445 -j ACCEPT
Feel free to change rules as per your setup. Save and close the file. Restart firewall service, enter:
# /sbin/services iptables restart
See this url for Iptables rules for SAMBA/CIFS clients.
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{ 4 comments… read them below or add one }
Thx. very much, nice overview :)
One note:
Ports 137 and 138 are UDP for samba. Cheers,
Please explain why $ grep -i NETBIOS /etc/services shows:
netbios-ns 137/tcp # NETBIOS Name Service
netbios-ns 137/udp
netbios-dgm 138/tcp # NETBIOS Datagram Service
netbios-dgm 138/udp
netbios-ssn 139/tcp # NETBIOS session service
netbios-ssn 139/udp
I.e. does above mean that 137/udp etc is not used?
Brilliant, thank you.