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Ports Required for Various Services/Applications

Tom Eastep

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover, and with no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”.

2006-01-22

Abstract

In addition to those applications described in the /etc/shorewall/rules documentation, here are some other services/applications that you may need to configure your firewall to accommodate.


Table of Contents

Important Notes
Auth (identd)
DNS
Emule
FTP
Gnutella
ICQ/AIM
IMAP
IPSEC
NFS
NTP (Network Time Protocol)
PCAnywhere
Pop3
PPTP
rdate
rsync
SSH/SFTP
SMB/NMB (Samba/Windows Browsing/File Sharing)
SMTP
SNMP
Telnet
TFTP
Traceroute
Usenet (NNTP)
VNC
Vonage
Web Access
Webmin
Whois
X/XDMCP
Other Source of Port Information
A. Revision History

Caution

This article applies to Shorewall 3.0 and later. If you are running a version of Shorewall earlier than Shorewall 3.0.0 then please see the documentation for that release

Important Notes

Note

Shorewall distribution contains a library of user-defined macros that allow for easily allowing or blocking a particular application. ls /usr/share/shorewall/macro.* for the list of macros in your distribution. If you find what you need, you simply use the macro in a rule. For example, to allow DNS queries from the dmz zone to the net zone:

#ACTION         SOURCE        DESTINATION
DNS/ACCEPT      dmz           net

Note

In the rules that are shown in this document, the ACTION is shown as ACCEPT. You may need to use DNAT (see FAQ 30) or you may want DROP or REJECT if you are trying to block the application.

Example: You want to port forward FTP from the net to your server at 192.168.1.4 in your DMZ. The FTP section below gives you:

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
FTP/ACCEPT     <source>  <destination>

You would code your rule as follows:

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
FTP/DNAT       net       dmz:192.168.1.4  

Auth (identd)

Caution

It is now the 21st Century ; don't use identd in production anymore.

#ACTION          SOURCE    DESTINATION      PROTO      DEST PORT(S)
Auth/ACCEPT      <source>  <destination>

DNS

#ACTION          SOURCE    DESTINATION      PROTO      DEST PORT(S)
DNS/ACCEPT       <source>  <destination>    

Note that if you are setting up a DNS server that supports recursive resolution, the server is the <destination> for resolution requests (from clients) and is also the <source> of recursive resolution requests (usually to other servers in the 'net' zone). So for example, if you have a public DNS server in your DMZ that supports recursive resolution for local clients then you would need:

#ACTION     SOURCE    DESTINATION      PROTO      DEST PORT(S)
DNS/ACCEPT  all       dmz              
DNS/ACCEPT  dmz       net              

Note

Recursive Resolution means that if the server itself can't resolve the name presented to it, the server will attempt to resolve the name with the help of other servers.

Emule

In contrast to how the rest of this article is organized, for emule I will give you the rules necessary to run emule on a single machine in your loc network (since that's what 99.99% of you want to do). Assume that:

  1. The internal machine running emule has IP address 192.168.1.4.

  2. You use Masquerading or SNAT for the local network.

  3. The zones are named as they are in the two- and three-interface QuickStart guides).

  4. Your loc->net policy is ACCEPT

/etc/shorewall/rules:

#ACTION     SOURCE   DESTINATION          PROTO         DEST PORT(S)
DNAT        net      loc:192.168.1.4      tcp           4662
DNAT        net      loc:192.168.1.4      udp           4672
DNAT        net      loc:192.168.1.4      tcp           4711

FTP

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
FTP/ACCEPT     <source>  <destination>

Look here for much more information.

Gnutella

  1. The internal machine running a Gnutella Client has IP address 192.168.1.4.

  2. You use Masquerading or SNAT for the local network.

  3. The zones are named as they are in the two- and three-interface QuickStart guides).

  4. Your loc->net policy is ACCEPT

#ACTION              SOURCE   DESTINATION      PROTO      DEST PORT(S)
Gnutella/DNAT        net      loc:192.168.1.4

ICQ/AIM

#ACTION     SOURCE    DESTINATION      PROTO      DEST PORT(S)
ICQ/ACCEPT  <source>  net

IMAP

Caution

When accessing you mail from the internet,use only IMAP over SSL

#ACTION         SOURCE    DESTINATION      PROTO      DEST PORT(S)
IMAP/ACCEPT     <source>  <destination> #Secure & Unsecure IMAP

IPSEC

#ACTION    SOURCE         DESTINATION      PROTO      DEST PORT(S)
ACCEPT     <source>       <destination>    50     
ACCEPT     <source>       <destination>    51
ACCEPT     <source>       <destination>    udp        500
ACCEPT     <destination>  <source>         50     
ACCEPT     <destination>  <source>         51
ACCEPT     <destination>  <source>         udp        500

Lots more information here and here.

NFS

#ACTION    SOURCE                         DESTINATION      PROTO      DEST PORT(S)
ACCEPT     <z1>:<list of client IPs>      <z2>:a.b.c.d     tcp        111
ACCEPT     <z1>:<list of client IPs>      <z2>:a.b.c.d     udp

For more NFS information, see http://sourceforge.net/mailarchive/forum.php?thread_id=8972145&forum_id=2270.

NTP (Network Time Protocol)

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
NTP/ACCEPT     <source>  <destination>

PCAnywhere

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
PCA/ACCEPT     <source>  <destination>

Pop3

Caution

If Possible , Avoid this protocol , use IMAP instead.

TCP Port 110 (Secure Pop3 is TCP Port 995)

#ACTION         SOURCE    DESTINATION      PROTO      DEST PORT(S)
POP3/ACCEPT     <source>  <destination> # Secure & Unsecure Pop3

PPTP

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
ACCEPT     <source>  <destination>    47    
ACCEPT     <source>  <destination>    tcp        1723

Lots more information here and here.

rdate

#ACTION          SOURCE    DESTINATION      PROTO      DEST PORT(S)
Rdate/ACCEPT     <source>  <destination>

rsync

#ACTION          SOURCE    DESTINATION      PROTO      DEST PORT(S)
Rsync/ACCEPT     <source>  <destination>

SSH/SFTP

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
SSH/ACCEPT <source>  <destination> 

SMB/NMB (Samba/Windows Browsing/File Sharing)

#ACTION        SOURCE         DESTINATION      PROTO      DEST PORT(S)
SMB/ACCEPT     <source>       <destination>
SMB/ACCEPT     <destination>  <source>

Also, see this page.

SMTP

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
SMTP/ACCEPT<source>  <destination>                      #Insecure SMTP
ACCEPT     <source>  <destination>    tcp        465    #SMTP over SSL (TLS)

SNMP

#ACTION         SOURCE    DESTINATION      PROTO      DEST PORT(S)
SNMP/ACCEPT     <source>  <destination>

Telnet

#ACTION           SOURCE    DESTINATION      PROTO      DEST PORT(S)
Telnet/ACCEPT     <source>  <destination>

TFTP

You must have TFTP connection tracking support in your kernel. If modularized, the modules are ip_conntrack_tftp (and ip_nat_tftp if any form of NAT is involved) These modules may be loaded using entries in /etc/shorewall/modules. The ip_conntrack_tftp module must be loaded first. Note that the /etc/shorewall/modules file released with recent Shorewall versions contains entries for these modules.

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
ACCEPT     <source>  <destination>    udp        69

Traceroute

#ACTION          SOURCE    DESTINATION      PROTO      DEST PORT(S)
Trcrt/ACCEPT     <source>  <destination>  #Good for 10 hops

UDP traceroute uses ports 33434 through 33434+<max number of hops>-1. Note that for the firewall to respond with a TTL expired ICMP reply, you will need to allow ICMP 11 outbound from the firewall. The standard Shorewall sample configurations all set this up for you automatically since those sample configurations enable all ICMP packet types originating on the firewall itself.

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
ACCEPT     fw        net              icmp
ACCEPT     fw        loc              icmp
ACCEPT     fw        ...

Usenet (NNTP)

#ACTION         SOURCE    DESTINATION      PROTO      DEST PORT(S)
NNTP/ACCEPT     <source>  <destination> 

TCP Port 119

VNC

Vncviewer to Vncserver -- TCP port 5900 + <display number>.

Vncviewer to Vncserver -- TCP port 5900 + <display number>.

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
ACCEPT     <source>  <destination>    tcp        5901               #Display Number 1
ACCEPT     <source>  <destination>    tcp        5902               #Display Number 2
...

Vncserver to Vncviewer in listen mode -- TCP port 5500.

#ACTION         SOURCE    DESTINATION      PROTO      DEST PORT(S)
VNCL/ACCEPT     <source>  <destination>

Vonage

The standard Shorewall loc->net ACCEPT policy is all that is required for Vonage™ IP phone service to work, provided that you have loaded the tftp helper modules (add the following entries to /etc/shorewall/modules if they are not there already):

    loadmodule ip_conntrack_tftp
    loadmodule ip_nat_tftp

Web Access

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
Web/ACCEPT     <source>  <destination> #Insecure HTTP& Secure HTTP

Webmin

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
Webmin/ACCEPT     <source>  <destination>  

Webmin use TCP port 10000.

Whois

#ACTION        SOURCE    DESTINATION      PROTO      DEST PORT(S)
Whois/ACCEPT     <source>  <destination>  

X/XDMCP

Assume that the Choser and/or X Server are running at <chooser> and the Display Manager/X applications are running at <apps>.

#ACTION    SOURCE    DESTINATION      PROTO      DEST PORT(S)
ACCEPT     <chooser> <apps>           udp        177         #XDMCP
ACCEPT     <apps>    <chooser>        tcp        6000:6009   #X Displays 0-9

Other Source of Port Information

Didn't find what you are looking for -- have you looked in your own /etc/services file?

Still looking? Try http://www.networkice.com/advice/Exploits/Ports

A. Revision History

Revision History
Revision 1.182005-11-23CR
Add Webmin info
Revision 1.172005-09-20TE
More 3.0 Updates
Revision 1.162005-09-02CR
Updated for Shorewall v3.0
Revision 1.152005-05-02TE
Added Emule
Revision 1.142004-10-01TE
Add rsync.
Revision 1.132004-09-21TE
Add note about ICMP type 11 to Traceroute.
Revision 1.122004-09-09TE
Add note about Vonage™.
Revision 1.112004-05-28TE
Corrected directory for actions.std and enhanced the DNS section.
Revision 1.102004-05-09TE
Added TFTP.
Revision 1.92004-04-24TE
Revised ICQ/AIM.
Revision 1.82004-04-23TE
Added SNMP.
Revision 1.72004-02-18TE
Make NFS work for everyone.
Revision 1.62004-02-14TE
Add PCAnywhere.
Revision 1.52004-02-05TE
Added information about VNC viewers in listen mode.
Revision 1.42004-01-26TE
Correct ICQ.
Revision 1.32004-01-04TE
Alphabetize
Revision 1.22004-01-03TE
Add rules file entries.
Revision 1.12002-07-30TE
Initial version converted to Docbook XML