Poste doch bitte mal das config-file hier, ohne das ist es
wirklich schwer, da was zu zu sagen. 
okay, Z. 401 ist FW_SERVICE_SAMBA=„yes“
Copyright © 2000-2002 SuSE GmbH Nuernberg, Germany. All rights reserved.
Author: Marc Heuse , 2002
Please contact me directly if you find bugs.
If you have problems getting this tool configures, please read this file
carefuly and take also a look into
-> /usr/share/doc/packages/SuSEfirewall2/EXAMPLES !
-> /usr/share/doc/packages/SuSEfirewall2/FAQ !
-> /usr/share/doc/packages/SuSEfirewall2/SuSEfirewall2.conf.EXAMPLE !
/etc/sysconfig/SuSEfirewall2
for use with /sbin/SuSEfirewall2 version 3.1 which is for 2.4 kernels!
------------------------------------------------------------------------
PLEASE NOTE THE FOLLOWING:
Just by configuring these settings and using the SuSEfirewall2 you are
not secure per se! There is *not* such a thing you install and hence you
are safed from all (security) hazards.
To ensure your security, you need also:
* Secure all services you are offering to untrusted networks (internet)
You can do this by using software which has been designed with
security in mind (like postfix, apop3d, ssh), setting these up without
misconfiguration and praying, that they have got really no holes.
SuSEcompartment can help in most circumstances to reduce the risk.
* Do not run untrusted software. (philosophical question, can you trust
SuSE or any other software distributor?)
* Harden your server(s) with the harden_suse package/script
* Recompile your kernel with the openwall-linux kernel patch
(former secure-linux patch, from Solar Designer) www.openwall.com
* Check the security of your server(s) regulary
* If you are using this server as a firewall/bastion host to the internet
for an internal network, try to run proxy services for everything and
disable routing on this machine.
* If you run DNS on the firewall: disable untrusted zone transfers and
either don’t allow access to it from the internet or run it split-brained.
Good luck!
Yours,
SuSE Security Team
------------------------------------------------------------------------
Configuration HELP:
If you have got any problems configuring this file, take a look at
/usr/share/doc/packages/SuSEfirewall2/EXAMPLES for an example.
All types have to set enable SuSEfirewall2 in the runlevel editor
If you are a end-user who is NOT connected to two networks (read: you have
got a single user system and are using a dialup to the internet) you just
have to configure (all other settings are OK): 2) and maybe 9).
If this server is a firewall, which should act like a proxy (no direct
routing between both networks), or you are an end-user connected to the
internet and to an internal network, you have to setup your proxys and
reconfigure (all other settings are OK): 2), 3), 9) and maybe 7), 11), 14)
If this server is a firewall, and should do routing/masquerading between
the untrusted and the trusted network, you have to reconfigure (all other
settings are OK): 2), 3), 5), 6), 9), and maybe 7), 10), 11), 12), 13),
14), 20)
If you want to run a DMZ in either of the above three standard setups, you
just have to configure *additionally* 4), 9), 12), 13), 17), 19).
If you know what you are doing, you may also change 8), 11), 15), 16)
and the expert options 19), 20), 21), 22) and 23) at the far end, but you
should NOT.
If you use diald or ISDN autodialing, you might want to set 17).
To get programs like traceroutes to your firewall to work is a bit tricky,
you have to set the following options to „yes“ : 11 (UDP only), 18 and 19.
Please note that if you use service names, that they exist in /etc/services.
There is no service „dns“, it’s called „domain“; email is called „smtp“ etc.
*Any* routing between interfaces except masquerading requires to set FW_ROUTE
to „yes“ and use FW_FORWARD or FW_ALLOW_CLASS_ROUTING !
If you just want to do masquerading without filtering, ignore this script
and run this line (exchange „ippp0“ „ppp0“ if you use a modem, not isdn):
iptables -A POSTROUTING -t nat -j MASQUERADE -o ippp0
echo 1 > /proc/sys/net/ipv4/ip_forward
and additionally the following lines to get at least a minimum of security:
iptables -A INPUT -j DROP -m state --state NEW,INVALID -i ippp0
iptables -A FORWARD -j DROP -m state --state NEW,INVALID -i ippp0
------------------------------------------------------------------------
1.)
Should the Firewall run in quickmode?
„Quickmode“ means that only the interfaces pointing to external networks
are secured, and no other. all interfaces not in the list of FW_DEV_EXT
are allowed full network access! Additionally, masquerading is
automatically activated for FW_MASQ_DEV devices. and last but not least:
all incoming connection via external interfaces are REJECTED.
You will only need to configure 2.) and FW_MASQ_DEV in 6.)
Optionally, you may add entries to section 9a.)
Choice: „yes“ or „no“, if not set defaults to „no“
FW_QUICKMODE=„no“
2.)
Which is the interface that points to the internet/untrusted networks?
Enter all the network devices here which are untrusted.
Choice: any number of devices, seperated by a space
e.g. „eth0“, „ippp0 ippp1 eth0:1“
FW_DEV_EXT=„eth0“
3.)
Which is the interface that points to the internal network?
Enter all the network devices here which are trusted.
If you are not connected to a trusted network (e.g. you have just a
dialup) leave this empty.
Choice: leave empty or any number of devices, seperated by a space
e.g. „tr0“, „eth0 eth1 eth1:1“ or „“
FW_DEV_INT=„eth0“
4.)
Which is the interface that points to the dmz or dialup network?
Enter all the network devices here which point to the dmz/dialups.
A „dmz“ is a special, seperated network, which is only connected to the
firewall, and should be reachable from the internet to provide services,
e.g. WWW, Mail, etc. and hence are at risk from attacks.
See /usr/share/doc/packages/SuSEfirewall2/EXAMPLES for an example.
Special note: You have to configure FW_FORWARD to define the services
which should be available to the internet and set FW_ROUTE to yes.
Choice: leave empty or any number of devices, seperated by a space
e.g. „tr0“, „eth0 eth1 eth1:1“ or „“
FW_DEV_DMZ=""
5.)
Should routing between the internet, dmz and internal network be activated?
REQUIRES: FW_DEV_INT or FW_DEV_DMZ
You need only set this to yes, if you either want to masquerade internal
machines or allow access to the dmz (or internal machines, but this is not
a good idea). This option supersedes IP_FORWARD from
/etc/sysconfig/network/options
Setting this option one alone doesn’t do anything. Either activate
massquerading with FW_MASQUERADE below if you want to masquerade your
internal network to the internet, or configure FW_FORWARD to define
what is allowed to be forwarded!
Choice: „yes“ or „no“, if not set defaults to „no“
FW_ROUTE=„no“
6.)
Do you want to masquerade internal networks to the outside?
REQUIRES: FW_DEV_INT or FW_DEV_DMZ, FW_ROUTE
„Masquerading“ means that all your internal machines which use services on
the internet seem to come from your firewall.
Please note that it is more secure to communicate via proxies to the
internet than masquerading. This option is required for FW_MASQ_NETS and
FW_FORWARD_MASQ.
Choice: „yes“ or „no“, if not set defaults to „no“
FW_MASQUERADE=„no“
You must also define on which interface(s) to masquerade on. This is
normally your external device(s) to the internet.
Most users can leave the default below.
e.g. „ippp0“ or „$FW_DEV_EXT“
FW_MASQ_DEV="$FW_DEV_EXT"
Which internal computers/networks are allowed to access the internet
directly (not via proxys on the firewall)?
Only these networks will be allowed access and will be masqueraded!
Choice: leave empty or any number of hosts/networks seperated by a space.
Every host/network may get a list of allowed services, otherwise everything
is allowed. A target network, protocol and service is appended by a comma to
the host/network. e.g. „10.0.0.0/8“ allows the whole 10.0.0.0 network with
unrestricted access. „10.0.1.0/24,0/0,tcp,80 10.0.1.0/24,0/0tcp,21“ allows
the 10.0.1.0 network to use www/ftp to the internet.
„10.0.1.0/24,tcp,1024:65535 10.0.2.0/24“ is OK too.
Set this variable to „0/0“ to allow unrestricted access to the internet.
FW_MASQ_NETS=""
7.)
Do you want to protect the firewall from the internal network?
REQUIRES: FW_DEV_INT
If you set this to „yes“, internal machines may only access services on
the machine you explicitly allow. They will be also affected from the
FW_AUTOPROTECT_SERVICES option.
If you set this to „no“, any user can connect (and attack) any service on
the firewall.
Choice: „yes“ or „no“, if not set defaults to „yes“
„yes“ is a good choice
FW_PROTECT_FROM_INTERNAL=„no“
8.)
Do you want to autoprotect all running network services on the firewall?
If set to „yes“, all network access to services TCP and UDP on this machine
will be prevented (except to those which you explicitly allow, see below:
FW_SERVICES_{EXT,DMZ,INT}_{TCP,UDP})
Choice: „yes“ or „no“, if not set defaults to „yes“
FW_AUTOPROTECT_SERVICES=„no“
9.)
Which services ON THE FIREWALL should be accessible from either the internet
(or other untrusted networks), the dmz or internal (trusted networks)?
(see no.13 & 14 if you want to route traffic through the firewall) XXX
Enter all ports or known portnames below, seperated by a space.
TCP services (e.g. SMTP, WWW) must be set in FW_SERVICES_*_TCP, and
UDP services (e.g. syslog) must be set in FW_SERVICES_*_UDP.
e.g. if a webserver on the firewall should be accessible from the internet:
FW_SERVICES_EXT_TCP=„www“
e.g. if the firewall should receive syslog messages from the dmz:
FW_SERVICES_DMZ_UDP=„syslog“
For IP protocols (like GRE for PPTP, or OSPF for routing) you need to set
FW_SERVICES_*_IP with the protocol name or number (see /etc/protocols)
Choice: leave empty or any number of ports, known portnames (from
/etc/services) and port ranges seperated by a space. Port ranges are
written like this: allow port 1 to 10 -> „1:10“
e.g. „“, „smtp“, „123 514“, „3200:3299“, „ftp 22 telnet 512:514“
For FW_SERVICES_*_IP enter the protocol name (like „igmp“) or number („2“)
Common: smtp domain
FW_SERVICES_EXT_TCP=„139“
Common: domain
FW_SERVICES_EXT_UDP=„139“
Common: domain
For VPN/Routing which END at the firewall!!
FW_SERVICES_EXT_IP=""
Common: smtp domain
FW_SERVICES_DMZ_TCP=""
Common: domain
FW_SERVICES_DMZ_UDP=""
For VPN/Routing which END at the firewall!!
FW_SERVICES_DMZ_IP=""
Common: ssh smtp domain
FW_SERVICES_INT_TCP=""
Common: domain syslog
FW_SERVICES_INT_UDP=""
For VPN/Routing which END at the firewall!!
FW_SERVICES_INT_IP=""
9a.)
External services in QUICKMODE.
This is only used for QUICKMODE (see 1.)!
(The settings here are similar to section 9.)
Which services ON THE FIREWALL should be accessible from either the
internet (or other untrusted networks), i.e. the external interface(s)
$FW_DEV_EXT
Enter all ports or known portnames below, seperated by a space.
TCP services (e.g. SMTP, WWW) must be set in FW_SERVICES_QUICK_TCP, and
UDP services (e.g. syslog) must be set in FW_SERVICES_QUICK_UDP.
e.g. if a secure shell daemon on the firewall should be accessible from
the internet:
FW_SERVICES_QUICK_TCP=„ssh“
e.g. if the firewall should receive isakmp (IPsec) internet:
FW_SERVICES_QUICK_UDP=„isakmp“
For IP protocols (like IPsec) you need to set
FW_SERVICES_QUICK_IP=„50“
Choice: leave empty or any number of ports, known portnames (from
/etc/services) and port ranges seperated by a space. Port ranges are
written like this: allow port 1 to 10 -> „1:10“
e.g. „“, „smtp“, „123 514“, „3200:3299“, „ftp 22 telnet 512:514“
For FW_SERVICES_*_IP enter the protocol name (like „igmp“) or number („2“)
QUICKMODE: TCP services open to external networks (InterNet)
(Common: ssh smtp)
FW_SERVICES_QUICK_TCP=""
QUICKMODE: UDP services open to external networks (InterNet)
(Common: isakmp)
FW_SERVICES_QUICK_UDP=""
QUICKMODE: IP protocols unconditionally open to external networks (InterNet)
(For VPN firewall that is VPN gateway: 50)
FW_SERVICES_QUICK_IP=""
10.)
Which services should be accessible from trusted hosts/nets?
Define trusted hosts/networks (doesnt matter if they are internal or
external) and the TCP and/or UDP services they are allowed to use.
Please note that a trusted host/net is *not* allowed to ping the firewall
until you set it to allow also icmp!
Choice: leave FW_TRUSTED_NETS empty or any number of computers and/or
networks, seperated by a space. e.g. „172.20.1.1 172.20.0.0/16“
Optional, enter a protocol after a comma, e.g. „1.1.1.1,icmp“
Optional, enter a port after a protocol, e.g. „2.2.2.2,tcp,22“
FW_TRUSTED_NETS=""
11.)
How is access allowed to high (unpriviliged [above 1023]) ports?
You may either allow everyone from anyport access to your highports („yes“),
disallow anyone („no“), anyone who comes from a defined port (portnumber or
known portname) [note that this is easy to circumvent!], or just your
defined nameservers („DNS“).
Note that you can’t use rpc requests (e.g. rpcinfo, showmount) as root
from a firewall using this script (well, you can if you include range
600:1023 in FW_SERVICES_EXT_UDP …).
Please note that with v2.1 „yes“ is not mandatory for active FTP from
the firewall anymore.
Choice: „yes“, „no“, „DNS“, portnumber or known portname,
if not set defaults to „no“
Common: „ftp-data“, better is „yes“ to be sure that everything else works 
FW_ALLOW_INCOMING_HIGHPORTS_TCP=„no“
Common: „DNS“ or „domain ntp“, better is „yes“ to be sure …
FW_ALLOW_INCOMING_HIGHPORTS_UDP=„DNS“
12.)
Are you running some of the services below?
They need special attention - otherwise they won´t work!
Set services you are running to „yes“, all others to „no“,
if not set defaults to „no“
If you want to offer the below services to your DMZ as well,
(and not just internally), set the switches below to „dmz“,
if you even want to offer to the world as well, set to „ext“
instead of „yes“ (NOT RECOMMENDED FOR SECURITY REASONS!)
FW_SERVICE_AUTODETECT=„yes“
Autodetect the services below when starting
If you are running bind/named set to yes. Remember that you have to open
port 53 (or „domain“) as udp/tcp to allow incoming queries.
Also FW_ALLOW_INCOMING_HIGHPORTS_UDP needs to be „yes“
FW_SERVICE_DNS=„no“
if you use dhclient to get an ip address you have to set this to „yes“ !
FW_SERVICE_DHCLIENT=„no“
set to „yes“ if this server is a DHCP server
FW_SERVICE_DHCPD=„no“
set to „yes“ if this server is running squid. You still have to open the
tcp port 3128 to allow remote access to the squid proxy service.
FW_SERVICE_SQUID=„no“
set to „yes“ if this server is running a samba server. You still have to
open the tcp port 139 to allow remote access to SAMBA.
FW_SERVICE_SAMBA=„yes“
13.)
Which services accessed from the internet should be allowed to the
dmz (or internal network - if it is not masqueraded)?
REQUIRES: FW_ROUTE
With this option you may allow access to e.g. your mailserver. The
machines must have valid, non-private, IP addresses which were assigned to
you by your ISP. This opens a direct link to your network, so only use
this option for access to your dmz!!!
Choice: leave empty (good choice!) or use the following explained syntax
of forwarding rules, seperated each by a space.
A forwarding rule consists of 1) source IP/net and 2) destination IP
seperated by a comma. e.g. „1.1.1.1,2.2.2.2 3.3.3.3/16,4.4.4.4/24“
Optional is a protocol, seperated by a comma, e.g. „5.5.5.5,6.6.6.6,igmp“
Optional is a port after the protocol with a comma, e.g. „0/0,0/0,udp,514“
FW_FORWARD=""
Beware to use this!
14.)
Which services accessed from the internet should be allowed to masqueraded
servers (on the internal network or dmz)?
REQUIRES: FW_ROUTE
With this option you may allow access to e.g. your mailserver. The
machines must be in a masqueraded segment and may not have public IP addesses!
Hint: if FW_DEV_MASQ is set to the external interface you have to set
FW_FORWARD from internal to DMZ for the service as well to allow access
from internal!
Please note that this should *not* be used for security reasons! You are
opening a hole to your precious internal network. If e.g. the webserver there
is compromised - your full internal network is compromised!!
Choice: leave empty (good choice!) or use the following explained syntax
of forward masquerade rules, seperated each by a space.
A forward masquerade rule consists of 1) source IP/net, 2) the IP to which
the requests will be forwarded to (in the dmz/intern net), 3) a protocol
(tcp/udp only!) and 4) destination port, seperated by a comma (","), e.g.
„4.0.0.0/8,1.1.1.1,tcp,80“
Optional is a port after the destination port, to redirect the request to
a different destination port on the destination IP, e.g.
„4.0.0.0/8,1.1.1.1,tcp,80,81“
Optional is an target IP address on which should the masquerading be decided.
You have to set the optional port option to use this.
Example:
200.200.200.0/24,10.0.0.10,tcp,80,81,202.202.202.202
The class C network 200.200.200.0/24 trying to access 202.202.202.202 port
80 will be forwarded to the internal server 10.0.0.10 on port 81.
Example:
200.200.200.0/24,10.0.0.10,tcp,80
The class C network 200.200.200.0/24 trying to access anything which goes
through this firewall ill be forwarded to the internal server 10.0.0.10 on
port 80
FW_FORWARD_MASQ=""
Beware to use this!
15.)
Which accesses to services should be redirected to a localport on the
firewall machine?
This can be used to force all internal users to surf via your squid proxy,
or transparently redirect incoming webtraffic to a secure webserver.
Choice: leave empty or use the following explained syntax of redirecting
rules, seperated by a space.
A redirecting rule consists of 1) source IP/net, 2) destination IP/net,
3) protocol (tcp or udp) 3) original destination port and 4) local port to
redirect the traffic to, seperated by a colon. e.g.:
„10.0.0.0/8,0/0,tcp,80,3128 0/0,172.20.1.1,tcp,80,8080“
Please note that as 2) destination, you may add ‚!‘ in front of the IP/net
to specify everything EXCEPT this IP/net.
FW_REDIRECT=""
16.)
Which logging level should be enforced?
You can define to log packets which were accepted or denied.
You can also the set log level, the critical stuff or everything.
Note that logging *_ALL is only for debugging purpose …
Choice: „yes“ or „no“, if not set FW_LOG_*_CRIT defaults to „yes“, and
FW_LOG_*_ALL defaults to „no“
FW_LOG_DROP_CRIT=„yes“
FW_LOG_DROP_ALL=„no“
FW_LOG_ACCEPT_CRIT=„yes“
FW_LOG_ACCEPT_ALL=„no“
only change/activate this if you know what you are doing!
FW_LOG="–log-level warning --log-tcp-options --log-ip-option --log-prefix SuSE-FW"
17.)
Do you want to enable additional kernel TCP/IP security features?
If set to yes, some obscure kernel options are set.
(icmp_ignore_bogus_error_responses, icmp_echoreply_rate,
icmp_destunreach_rate, icmp_paramprob_rate, icmp_timeexeed_rate,
ip_local_port_range, log_martians, mc_forwarding, mc_forwarding,
rp_filter, routing flush)
Tip: Set this to „no“ until you have verified that you have got a
configuration which works for you. Then set this to „yes“ and keep it
if everything still works. (It should!) 
Choice: „yes“ or „no“, if not set defaults to „yes“
FW_KERNEL_SECURITY=„yes“
18.)
Keep the routing set on, if the firewall rules are unloaded?
REQUIRES: FW_ROUTE
If you are using diald, or automatic dialing via ISDN, if packets need
to be sent to the internet, you need to turn this on. The script will then
not turn off routing and masquerading when stopped.
You *might* also need this if you have got a DMZ.
Please note that this is *insecure*! If you unload the rules, but are still
connected, you might your internal network open to attacks!
The better solution is to remove „/sbin/SuSEfirewall2 stop“ or
„/sbin/init.d/firewall stop“ from the ip-down script!
Choices „yes“ or „no“, if not set defaults to „no“
FW_STOP_KEEP_ROUTING_STATE=„no“
19.)
Allow (or don’t) ICMP echo pings on either the firewall or the dmz from
the internet? The internet option is for allowing the DMZ and the internal
network to ping the internet.
REQUIRES: FW_ROUTE for FW_ALLOW_PING_DMZ and FW_ALLOW_PING_EXT
Choice: „yes“ or „no“, defaults to „no“ if not set
FW_ALLOW_PING_FW=„yes“
FW_ALLOW_PING_DMZ=„no“
FW_ALLOW_PING_EXT=„no“
END of /etc/sysconfig/SuSEfirewall2
#-------------------------------------------------------------------------#
EXPERT OPTIONS - all others please don’t change these!
#-------------------------------------------------------------------------#
20.)
Allow (or don’t) ICMP time-to-live-exceeded to be send from your firewall.
This is used for traceroutes to your firewall (or traceroute like tools).
Please note that the unix traceroute only works if you say „yes“ to
FW_ALLOW_INCOMING_HIGHPORTS_UDP, and windows traceroutes only if you say
additionally „yes“ to FW_ALLOW_PING_FW
Choice: „yes“ or „no“, if not set defaults to „no“
FW_ALLOW_FW_TRACEROUTE=„yes“
21.)
Allow ICMP sourcequench from your ISP?
If set to yes, the firewall will notice when connection is choking, however
this opens yourself to a denial of service attack. Choose your poison.
Choice: „yes“ or „no“, if not set defaults to „yes“
FW_ALLOW_FW_SOURCEQUENCH=„yes“
22.)
Allow/Ignore IP Broadcasts?
If set to yes, the firewall will not filter broadcasts by default.
This is needed e.g. for Netbios/Samba, RIP, OSPF where the broadcast
option is used.
If you do not want to allow them however ignore the annoying log entries,
set FW_IGNORE_FW_BROADCAST to yes.
Choice: „yes“ or „no“, if not set defaults to „no“
FW_ALLOW_FW_BROADCAST=„no“
FW_IGNORE_FW_BROADCAST=„yes“
23.)
Allow same class routing per default?
REQUIRES: FW_ROUTE
Do you want to allow routing between interfaces of the same class
(e.g. between all internet interfaces, or all internal network interfaces)
be default (so without the need setting up FW_FORWARD definitions)?
Choice: „yes“ or „no“, if not set defaults to „no“
FW_ALLOW_CLASS_ROUTING=„no“
25.)
Do you want to load customary rules from a file?
This is really an expert option. NO HELP WILL BE GIVEN FOR THIS!
READ THE EXAMPLE CUSTOMARY FILE AT /etc/sysconfig/SuSEfirewall2-custom
#FW_CUSTOMRULES="/etc/sysconfig/SuSEfirewall2-custom"
FW_CUSTOMRULES=""
26.)
Do you want to REJECT packets instead of DROPing?
DROPing (which is the default) will make portscans and attacks much
slower, as no replies to the packets will be sent. REJECTing means, that
for every illegal packet, a connection reject packet is sent to the
sender.
Choice: „yes“ or „no“, if not set defaults to „no“
FW_REJECT=„no“
