Re: exact iptables command to stop a source from accessing a Linux cluster

[sunhux G <sunhux@xxxxxxxxx>]

 

I can't even start up iptables as the previous admin hardened it

(but not sure how / where he hardened it)

 

So despite that I do

service iptables start,

"service iptables status" still show "Firewall is stopped"

 

Now, can I use /etc/hosts.deny instead ?

Do I need to do "pkill -HUP tcpd"   or

"service xinetd restart"   - which of the two

commands shd I execute & what's the syntax

in /etc/hosts.deny ?

 

Thanks

On Fri, Sep 18, 2009 at 11:38 AM, Ian Hayes <cthulhucalling@xxxxxxxxx> wrote:

[root@cthulhu ~]# iptables -L --line-numbers
Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination
1    DROP       all  --  10.5.5.5             anywhere
2    DROP       all  --  10.5.5.6             anywhere
3    DROP       all  --  10.5.5.7             anywhere

Find the rule number that matches the one you want to delete. Say you want to delete #2 from the INPUT table

[root@cthulhu ~]# iptables -D INPUT 2
[root@cthulhu ~]# iptables -L --line-numbers
Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination
1    DROP       all  --  10.5.5.5             anywhere
2    DROP       all  --  10.5.5.7             anywhere


Or you can do iptables -F which will basically drop all your iptables. Make sure you've saved recently before you do that.

On Thu, Sep 17, 2009 at 8:22 PM, sunhux G <sunhux@xxxxxxxxx> wrote:

Thanks Ian.

 

So I issue this command on both cluster nodes and it will also

stop access to the virtual cluster address?

 

What's the command to reverse / remove
" iptables -A INPUT -s 10.5.5.25 -j DROP " ?

Just in case there's a problem, I'll need to reverse.

 

Tks

U

On Fri, Sep 18, 2009 at 10:36 AM, Ian Hayes <cthulhucalling@xxxxxxxxx> wrote:

iptables -A INPUT -s 10.5.5.25 -j DROP

On Thu, Sep 17, 2009 at 7:33 PM, sunhux G <sunhux@xxxxxxxxx> wrote:

 

Hi,

 

I have a RHEL 5.1  cluster that's constantly being accessed by an

application from a Windows server application via sqlnet (ie Tcp

port 1521) which caused a specific Oracle accounts to be locked.

 

The owner of the Windows box does not know why the Filenet

application is doing this so while she's doing the research which

configuration in Filenet needs to be fixed to stop this, we need an

interim measure to block this Windows server's access to the cluster.

 

Thus I would like to set up iptables / firewall on this Linux box to

stop the sqlnet access.  Can someone provide me some example

commands / syntax ?

 

Source IP address : 10.5.5.25   (Windows server)

Tcp port : 1521

My Linux boxes IP address :  10.5.5.46 / .47

My Linux cluster virtual addr : 10.5.5.45

 

In fact I would like to block on all ports on the Linux cluster to stop

this Windows server from accessing it.  So what's the exact commands

I should issue on each of the Linux box?  Would iptables also block

the Windows server from accessing the cluster virtual IP addr?

 

 

Thanks

U

 

 

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