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DISCUSSION Subba Rao 3 participants 3 messages Jan 14, 2003 – Jan 17, 2003

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Subba Rao

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#0 lore raw

Hi

I have the following rules to allow traffic on SMTP port.

--------------------

iptables -A INPUT -i $EXTERNAL_IF -p tcp --destination-port 25 -j LOG \
                --log-level 4 --log-prefix "Incoming Mail Traffic "

iptables -A INPUT -i $EXTERNAL_IF -p tcp --destination-port 25 -j ACCEPT
--------------------

The default policy is on the INPUT chain is to drop the packets. How do I capture what is being dropped?

My goal is to log the inbound traffic and my syslog has the following configuration:

--------------------

*.=info;*.=notice;mail.none                     /usr/adm/messages
*.=alert                                        /usr/adm/messages
*.=crit                                         /usr/adm/debug
mail.*                                          /var/log/mail-log
kern.*                                          /var/log/messages
user.*                                          /var/log/messages
syslog.*                                        /var/log/messages
auth.*                                          /var/log/messages
authpriv.*                                      /var/log/messages

--------------------

Is this configuration sufficient to capture the inbound connections?

Signature · 2 lines
Subba Rao
[email protected]
#1 lore raw
Quoted 8 lines · Subba Rao

--------------------

iptables -A INPUT -i $EXTERNAL_IF -p tcp --destination-port 25 -j LOG \
                --log-level 4 --log-prefix "Incoming Mail Traffic "

iptables -A INPUT -i $EXTERNAL_IF -p tcp --destination-port 25 -j ACCEPT
--------------------

The default policy is on the INPUT chain is to drop the packets. How do I capture what is being dropped?

  iptables -A INPUT -i $EXTERNAL_IF -j LOG --log-level 4 \
  	--log-prefix "Dropped Incoming "

Remember a LOG target simply LOGs then returns, so it'll still drop through to the policy after this.

Quoted 9 lines

My goal is to log the inbound traffic and my syslog has the following configuration:

--------------------

*.=info;*.=notice;mail.none                     /usr/adm/messages
*.=alert                                        /usr/adm/messages
*.=crit                                         /usr/adm/debug
mail.*                                          /var/log/mail-log
kern.*                                          /var/log/messages

All iptables -j LOG goes to kern.*, so you should see it in your
/var/log/messages. You could also use --log-level 7 (DEBUG) instead and:

kern.=debug /var/log/iptables

Note you _CAN_ also do --log-level debug to make things clearer.

HTH,

-Ath

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#2 lore raw
In reply to Subba Rao
Quoted 26 lines · Subba Rao

Hi

I have the following rules to allow traffic on SMTP port.

--------------------

iptables -A INPUT -i $EXTERNAL_IF -p tcp --destination-port 25 -j LOG \
                --log-level 4 --log-prefix "Incoming Mail Traffic "

iptables -A INPUT -i $EXTERNAL_IF -p tcp --destination-port 25 -j ACCEPT
--------------------

The default policy is on the INPUT chain is to drop the packets. How do I capture what is being dropped?

My goal is to log the inbound traffic and my syslog has the following configuration:

--------------------

*.=info;*.=notice;mail.none                     /usr/adm/messages
*.=alert                                        /usr/adm/messages
*.=crit                                         /usr/adm/debug
mail.*                                          /var/log/mail-log
kern.*                                          /var/log/messages
user.*                                          /var/log/messages
syslog.*                                        /var/log/messages
auth.*                                          /var/log/messages
authpriv.*                                      /var/log/messages
Quoted 9 lines

--------------------

Is this configuration sufficient to capture the inbound connections?

Signature · 2 lines
Subba Rao
[email protected]

Hi Rao,

Just add a rule after the default policy. This should give you all the
packets which are dropped.

iptables -A INPUT -j LOG
iptables -A OUTPUT -j LOG
iptables -A FORWARD -j LOG

Signature · 2 lines
Dharmendra.T
Linux Enthu