Firewall blocking Java applet?

Firewall blocking Java applet?

[Jong Hian Zin]

I have a Linksys WRT54G running OpenWRT, the WAN port is connecting to an 
ADSL modem (PPPoE) and there are 2 PCs connecting to the WRT54G's LAN ports. 
I can surf the web from any of the PCs except doing bandwidth test using 
this website:

http://202.188.95.52:8080/speedometer/

The bandwidth test Java applet can be loaded, but unable to start the test. 
The following is my script:

#!/bin/sh
. /etc/functions.sh
export WAN=$(nvram get wan_ifname)
export LAN=$(nvram get lan_ifname)

## CLEAR TABLES
for T in filter nat mangle; do
  iptables -t $T -F
  iptables -t $T -X

done

iptables -N input_rule
iptables -N output_rule
iptables -N forwarding_rule

iptables -t nat -N prerouting_rule
iptables -t nat -N postrouting_rule

### Port forwarding
# iptables -t nat -A prerouting_rule -p tcp --dport 22 -j DNAT --to 
192.168.1.2 <http://192.168.1.2>
# iptables        -A forwarding_rule -p tcp --dport 22 -d 192.168.1.2
<http://192.168.1.2> -j ACCEPT

### INPUT
###  (connections with the router as destination)


  # base case
  iptables -P INPUT DROP
  iptables -A INPUT -m state --state INVALID -j DROP
  iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

  # allow
  iptables -A INPUT -i \! $WAN -j ACCEPT        # allow from lan/wifi interfaces

  iptables -A INPUT -p icmp -j ACCEPT           # allow ICMP
  iptables -A INPUT -p tcp --dport 22 -j ACCEPT
  iptables -A INPUT -p 47 -j ACCEPT             # allow GRE
  #
  # insert accept rule or to jump to new accept-check table here

  #
  iptables -A INPUT -j input_rule

  # reject (what to do with anything not allowed earlier)
  iptables -A INPUT -p tcp --syn --tcp-option \! 2 -j  DROP
  iptables -A INPUT -p tcp -j REJECT --reject-with tcp-reset

  iptables -A INPUT -j REJECT --reject-with icmp-port-unreachable

### OUTPUT
### (connections with the router as source)

  # base case
  iptables -P OUTPUT DROP
  iptables -A OUTPUT -m state --state INVALID -j DROP

  iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

  # allow
  iptables -A OUTPUT -j ACCEPT          #allow everything out
  #
  # insert accept rule or to jump to new accept-check table here

  #
  iptables -A OUTPUT -j output_rule

  # reject (what to do with anything not allowed earlier)
  iptables -A OUTPUT -p tcp -j REJECT --reject-with tcp-reset
  iptables -A OUTPUT -j REJECT --reject-with icmp-port-unreachable


### FORWARDING
### (connections routed through the router)

  # base case
  iptables -P FORWARD DROP
  iptables -A FORWARD -m state --state INVALID -j DROP
  iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT

  iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS
--clamp-mss-to-pmtu

  # allow
  iptables -A FORWARD -i br0 -o br0 -j ACCEPT
  iptables -A FORWARD -i $LAN -o $WAN -j ACCEPT
  #
  # insert accept rule or to jump to new accept-check table here

  #
  iptables -A FORWARD -j forwarding_rule

  # reject (what to do with anything not allowed earlier)
  # uses the default -P DROP

### MASQ
  iptables -t nat -A PREROUTING -j prerouting_rule

  iptables -t nat -A POSTROUTING -j postrouting_rule
  iptables -t nat -A POSTROUTING -o $WAN -j MASQUERADE


Any idea what is blocking the bandwidth test Java applet?

Thanks,

-- 
Jong Hian Zin

Re: Firewall blocking Java applet?

[/dev/rob0]

On Wednesday 22 June 2005 20:36, Jong Hian Zin wrote:
> http://202.188.95.52:8080/speedometer/
>
> The bandwidth test Java applet can be loaded, but unable to start the

Does it work if not going through the OpenWRT?

>   iptables -A INPUT -m state --state INVALID -j DROP
>   iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

You could consolidate these INPUT rules with the ones in FORWARD and 
OUTPUT. I use a chain named "State" which I call from INPUT and 
FORWARD. (I don't do OUTPUT filtering, seems pointless to me.)

>   iptables -A INPUT -p tcp --dport 22 -j ACCEPT

You're DNAT'ing your 22/tcp, so that would hit the FORWARD chain.

>   iptables -A INPUT -j input_rule

These "*_rule" chains do not appear to be used for anything.

> Any idea what is blocking the bandwidth test Java applet?

Not from what you posted. iptables-save(8) would be easier to follow. 
But you can probably troubleshoot this on your own by putting in -j LOG 
rules for -s/-d 202.188.95.52 traffic. Try it and see what you get. Is 
the openwrt capable of normal logging? Or maybe to a remote syslog 
server?
-- 
    mail to this address is discarded unless "/dev/rob0"
    or "not-spam" is in Subject: header

Re: Firewall blocking Java applet?

[Jong Hian Zin]

On 6/23/05, /dev/rob0 <rob0@gmx.co.uk> wrote:
> 
> On Wednesday 22 June 2005 20:36, Jong Hian Zin wrote:
> > http://202.188.95.52:8080/speedometer/
> >
> > The bandwidth test Java applet can be loaded, but unable to start the
> 
> Does it work if not going through the OpenWRT?


Yes, it works if I connect the PC directly to the ADSL modem, using PPPoE.

Not from what you posted. iptables-save(8) would be easier to follow.
> But you can probably troubleshoot this on your own by putting in -j LOG
> rules for -s/-d 202.188.95.52 <http://202.188.95.52> traffic. Try it and 
> see what you get. Is
> the openwrt capable of normal logging? Or maybe to a remote syslog
> server?
> 

I will try iptables-save and logging.

-- 
Jong Hian Zin

Re: Firewall blocking Java applet?

[Jong Hian Zin]

I have managed to log the traffic right after I clicked on the Start button:

root@OpenWrt:~# iptables -I FORWARD 1 -s 0/0 -d 0/0 -j LOG
root@OpenWrt:~# logread -f
Jun 27 22:08:49 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=127 ID=3703
PROTO=UDP SPT=137 DPT=137 LEN=58
Jun 27 22:08:51 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=127 ID=3705
PROTO=UDP SPT=137 DPT=137 LEN=58
Jun 27 22:08:52 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=127 ID=3707
PROTO=UDP SPT=137 DPT=137 LEN=58
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=48 TOS=0x00 PREC=0x00 TTL=127 ID=3709 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64240 RES=0x00 SYN URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=48 TOS=0x00 PREC=0x00 TTL=122 ID=10970 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65535 RES=0x00 ACK SYN URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=40 TOS=0x00 PREC=0x00 TTL=127 ID=3710 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64240 RES=0x00 ACK URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=94 TOS=0x00 PREC=0x00 TTL=122 ID=10973 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65535 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=51 TOS=0x00 PREC=0x00 TTL=127 ID=3711 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64186 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=73 TOS=0x00 PREC=0x00 TTL=122 ID=10977 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65524 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=54 TOS=0x00 PREC=0x00 TTL=127 ID=3714 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64153 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=68 TOS=0x00 PREC=0x00 TTL=122 ID=10985 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65510 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=40 TOS=0x00 PREC=0x00 TTL=127 ID=3716 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64125 RES=0x00 ACK URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=66 TOS=0x00 PREC=0x00 TTL=122 ID=11013 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65510 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=48 TOS=0x00 PREC=0x00 TTL=127 ID=3717 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64099 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=60 TOS=0x00 PREC=0x00 TTL=122 ID=11022 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65502 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=46 TOS=0x00 PREC=0x00 TTL=127 ID=3718 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64079 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=92 TOS=0x00 PREC=0x00 TTL=122 ID=11029 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65496 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=127 ID=3719
PROTO=UDP SPT=137 DPT=137 LEN=58
Jun 27 22:08:54 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
210.187.132.33 <http://210.187.132.33> DST=192.168.1.2
<http://192.168.1.2>LEN=56 TOS=0x00 PREC=0x00 TTL=252 ID=0 PROTO=ICMP
TYPE=3 CODE=13 [SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=125 ID=3719
PROTO=UDP SPT=137 DPT=137 LEN=58 ]
Jun 27 22:08:54 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=40 TOS=0x00 PREC=0x00 TTL=127 ID=3720 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64027 RES=0x00 ACK URGP=0
Jun 27 22:08:56 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=127 ID=3723
PROTO=UDP SPT=137 DPT=137 LEN=58
Jun 27 22:08:57 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=78 TOS=0x00 PREC=0x00 TTL=127 ID=3725
PROTO=UDP SPT=137 DPT=137 LEN=58
Jun 27 22:08:59 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=48 TOS=0x00 PREC=0x00 TTL=127 ID=3727 DF
PROTO=TCP SPT=4848 DPT=3265
WINDOW=64240 RES=0x00 SYN URGP=0
Jun 27 22:08:59 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=48 TOS=0x00 PREC=0x00 TTL=122 ID=11818 DF
PROTO=TCP SPT=3265 DPT=4848
WINDOW=65535 RES=0x00 ACK SYN URGP=0
Jun 27 22:08:59 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=40 TOS=0x00 PREC=0x00 TTL=127 ID=3728 DF
PROTO=TCP SPT=4848 DPT=3265
WINDOW=64240 RES=0x00 ACK URGP=0
Jun 27 22:08:59 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=52 TOS=0x00 PREC=0x00 TTL=127 ID=3729 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=64027 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:59 (none) kern.warn kernel: IN=ppp0 OUT=br0 PHYSOUT=vlan0 SRC=
219.93.175.234 <http://219.93.175.234> DST=192.168.1.2
<http://192.168.1.2>LEN=94 TOS=0x00 PREC=0x00 TTL=122 ID=11828 DF
PROTO=TCP SPT=21 DPT=4847
WINDOW=65484 RES=0x00 ACK PSH URGP=0
Jun 27 22:08:59 (none) kern.warn kernel: IN=br0 OUT=ppp0 PHYSIN=vlan0 SRC=
192.168.1.2 <http://192.168.1.2> DST=219.93.175.234
<http://219.93.175.234>LEN=40 TOS=0x00 PREC=0x00 TTL=127 ID=3731 DF
PROTO=TCP SPT=4847 DPT=21
WINDOW=63973 RES=0x00 ACK URGP=0

Does these tell anything?

On 6/23/05, Jong Hian Zin <mail.zin@gmail.com> wrote:
> 
> On 6/23/05, /dev/rob0 <rob0@gmx.co.uk> wrote:
> > 
> > On Wednesday 22 June 2005 20:36, Jong Hian Zin wrote:
> > > http://202.188.95.52:8080/speedometer/
> > >
> > > The bandwidth test Java applet can be loaded, but unable to start the 
> > 
> > Does it work if not going through the OpenWRT?
> 
> 
> Yes, it works if I connect the PC directly to the ADSL modem, using PPPoE.
> 
> Not from what you posted. iptables-save(8) would be easier to follow.
> > But you can probably troubleshoot this on your own by putting in -j LOG 
> > rules for -s/-d 202.188.95.52 <http://202.188.95.52> traffic. Try it and 
> > see what you get. Is
> > the openwrt capable of normal logging? Or maybe to a remote syslog
> > server?
> > 
> 
> I will try iptables-save and logging. 
> 
> -- 
> Jong Hian Zin 




-- 
Jong Hian Zin