Mailing List Archive

Hi thanks, could you explain what this line does ?

This is what I understand :

Foward incomming form eth0 to Output eth1 with tcp port 21 but I dont
understant the --syn or exactly what this whole line does ...

Patrik a écrit :
> Richard, try to use
>
> # iptables -A FORWARD -i eth0 -o eth1 -p tcp --syn --dport 21 -j ACCEPT
>
> I think that´s solve
>
>
> Chorus Informatica
> Patrik Souza - Diretor
> Fone: 11 5621-6177
> Mobile: 11 8154-0794
>
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> -----Mensagem original-----
> De: netfilter-bounces@lists.netfilter.org
> [mailto:netfilter-bounces@lists.netfilter.org] Em nome de Richard
> Enviada em: sábado, 18 de agosto de 2007 16:09
> Para: netfilter@lists.netfilter.org
> Assunto: IPtables settings to access a backup FTP
>
> Hello, this is my first message so I hope I'm doing this right ! :)
>
> I've got iptables setup and running well on my server and up to now I've
> not had any problems, however I have just installed a backup system
> which needs to connect by FTP to a distant server.
>
> With my firewall disactivated all works fine, however with the firewall
> activated when I use the "ls" command of the debian ftp command line
> package (CWD) I get:
>
> 200 ok then a long wait then :
> 421 Service not available, remote server has closed connection.
>
> I've tried this on two different FTP's and it only works if the firewall
> is disactivated.
>
> One server is a plesk server but the server I need to connect to I do
> not know much about, with filezilla on my pc I've managed to connect to
> it with both FTP active and FTP passive so I guess it can do both.
>
> On my server I just do :
>
> ftp ftp.server.com
> username
> password
>
> So I'm not sure if it connects as passive or active.
>
> These are the ports that I have got open :
>
> -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
> -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
>
> -A INPUT -p tcp -m tcp --dport 20 -j ACCEPT
> -A INPUT -p tcp -m tcp --dport 21 -j ACCEPT
>
> -A OUTPUT -p tcp -m tcp --dport 20 -j ACCEPT
> -A OUTPUT -p tcp -m tcp --dport 21 -j ACCEPT
>
> Which ports do you suggest I should open to connect to this FTP server ?
>
> Thanks in advance,
>
> Richard
>
>
>