[tproxy] iptables setup for Zorp

Tim Feld zolists at gmx.de
Wed May 28 17:38:24 CEST 2008


Hi,

I am having difficulties to transfer the zorp tutorial iptables setup to the new tproxy version without the tproxy table. 

This is the setup in iptables-save/restore syntax found at balabit's website (https://www.balabit.com/network-security/zorp-gateway/gpl/tutorial/):
*tproxy
:PREROUTING ACCEPT
:OUTPUT ACCEPT
:PRintra -
:PRinter -
:PRdmz -
-A PREROUTING -i IFintra -j PRintra
-A PREROUTING -i IFinter -j PRinter
-A PREROUTING -i IFdmz   -j PRdmz
// PRintra chain
-A PRintra -p tcp --dport 80 -j TPROXY --on-port 50080
-A PRintra -p tcp --dport 443 -j TPROXY --on-port 50443
-A PRintra -p tcp --dport 21 -j TPROXY --on-port 50021
// PRinter chain
-A PRinter -p tcp --dport 80 -j TPROXY --on-port 50080
// PRdmz chain
// no services permitted
COMMIT
*filter
:INPUT DENY
:FORWARD DENY
:OUTPUT ACCEPT
:noise -
:spoof -
:spoofdrop DROP
:LOintra -
:LOinter -
:LOdmz -
-A INPUT -j noise
-A INPUT -j spoof
// permit all traffic initiated by transparent proxies
-A INPUT -m tproxy  -j ACCEPT
//
// permit all TCP traffic initiated by local processes, or allowed by rules
// below, we don't trust the state match for UDP traffic, they will be handled
// by individual rules below.
//
-A INPUT -p tcp -m state --state ESTABLISHED,RELATED -j ACCEPT
// permit all loopback traffic
-A INPUT -i lo -j ACCEPT
-A INPUT -i IFintra -j LOintra
-A INPUT -i IFinter -j LOinter
-A INPUT -i IFdmz   -j LOdmz
-A INPUT -j DROP
-A FORWARD -j LOG --log-prefix "FORWARD DROP: "
-A FORWARD -j DROP
// LOintra
-A LOintra -p udp --dport 53 -j ACCEPT
-A LOintra -p udp --dport 123 -j ACCEPT
-A LOintra -p tcp --syn --dport 25 -j ACCEPT
-A LOintra -j LOG --log-prefix "LOintra DROP: "
-A LOintra -j DROP
// LOinter
// permit DNS replies, bind is configured to send out DNS packets from this
// port. We could also use the state match in our INPUT chain.
-A LOinter -p udp -s DNS_SERVERS --dport 53000 -j ACCEPT
-A LOinter -p udp -s NTP_SERVERS --dport 123 -j ACCEPT
-A LOinter -p tcp --syn --dport 25 -j ACCEPT
-A LOinter -j LOG --log-prefix "LOinter DROP: "
-A LOinter -j DROP
// LOdmz
-A LOdmz -p udp --dport 53 -j ACCEPT
-A LOdmz -p udp --dport 123 -j ACCEPT
-A LOdmz -p tcp --syn --dport 25 -j ACCEPT
-A LOdmz -j LOG --log-prefix "LOdmz DROP: "
-A LOdmz -j DROP
//
// noise chain, should drop all packets which need not be logged,
// otherwise it should return to the main ruleset
//
-A noise -p udp --dport 137:139 -j DROP
-A noise -j RETURN
//
// spoof chain, should drop all packets with spoofed source address
// otherwise it should return to the main ruleset
//
-A spoof -i lo -j RETURN
-A spoof ! -i lo -s 127.0.0.0/8 -j spoofdrop
-A spoof -i IFintra ! -s NETintra -j spoofdrop
-A spoof ! -i IFintra -s NETintra -j spoofdrop
-A spoof -i IFdmz ! -s NETdmz -j spoofdrop
-A spoof ! -i IFdmz -s NETdmz -j spoofdrop
-A spoof -j RETURN
//
-A spoofdrop -j LOG --log-prefix "Spoofed packet: "
-A spoofdrop -j DROP
COMMIT


I tried to do the tproxy table stuff in mangle but did not succeed. All packets are dropped. Apart from that I do not know how to replace -A INPUT -m tproxy -j ACCEPT.

I really hope someone can help me.

Thanks 
Tim
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