Redhat Linux 8.0 IPtables help

Redhat Linux 8.0 IPtables help

[Sundaram Ramasamy]

Hi,



I have Linux machine with single Network interface. I want to block all the
tcp,udp and icmp port's other then 22,23,24 and 80.



Can you verify the following script?





IPTABLES=/sbin/iptables



$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP

$IPTABLES -A INPUT -p tcp -m multiport --destination-port 22,23,24,80 -j
ACCEPT



$IPTABLES -A INPUT -p udp -m multiport --destination-port 22,23,24,80 -j
ACCEPT





What port should I block for icmp protocol?



-SR

Re: Redhat Linux 8.0 IPtables help

[Dharmendra.T]

[-- Attachment #1: Type: text/plain, Size: 1260 bytes --]

On Fri, 2003-06-06 at 01:02, Sundaram Ramasamy wrote:

    Hi,
    
    
    
    I have Linux machine with single Network interface. I want to block all the
    tcp,udp and icmp port's other then 22,23,24 and 80.
    
    
    
    Can you verify the following script?
    
    
    
    
    
    IPTABLES=/sbin/iptables
    
    
    
    $IPTABLES -P INPUT DROP
    $IPTABLES -P OUTPUT DROP
    $IPTABLES -P FORWARD DROP
    
    $IPTABLES -A INPUT -p tcp -m multiport --destination-port 22,23,24,80 -j
    ACCEPT
    
    
    
    $IPTABLES -A INPUT -p udp -m multiport --destination-port 22,23,24,80 -j
    ACCEPT
    
    
    
    
    
    What port should I block for icmp protocol?
    
    
    
    -SR
    
    	You have to add the following rules to enable the communication.
    

$IPTABLES -A OUTPUT -p tcp -m multiport --source-port 22,23,24,80 -j
ACCEPT
$IPTABLES -A OUTPUT -p udp -m multiport --source-port 22,23,24,80 -j
ACCEPT


-- 
Regards
Dharmendra.T


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RE: Redhat Linux 8.0 IPtables help

[George Vieira]

"What port should I block for icmp protocol?"
Errrr??... your blocking them already??? Or did you mean, which icmp should you ACCEPT?

-------------------------
$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP
-------------------------

BTW, why are you allowing UDP 22,23,80??? It's not used for ssh,telnet and http and whatever 24 is.. (can't be bothered). he he ;P

Thanks,
____________________________________________
George Vieira
Systems Manager
georgev@citadelcomputer.com.au

Citadel Computer Systems Pty Ltd
http://www.citadelcomputer.com.au

-----Original Message-----
From: Sundaram Ramasamy [mailto:sun@percipia.com]
Sent: Friday, June 06, 2003 5:33 AM
To: netfilter@lists.netfilter.org
Subject: Redhat Linux 8.0 IPtables help


Hi,



I have Linux machine with single Network interface. I want to block all the
tcp,udp and icmp port's other then 22,23,24 and 80.



Can you verify the following script?

IPTABLES=/sbin/iptables

$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP

$IPTABLES -A INPUT -p tcp -m multiport --destination-port 22,23,24,80 -j
ACCEPT



$IPTABLES -A INPUT -p udp -m multiport --destination-port 22,23,24,80 -j
ACCEPT





What port should I block for icmp protocol?



-SR