Ok, figured out how to do what you asked, used PuTTy to do it, then figured out I already had the ability to do it built in (ala Run Cmd tab), lol.
Code:
ASUSWRT-Merlin RT-AC66U_3.0.0.4 Fri Nov 1 23:26:23 UTC 2013
admin@RT-AC66U:/tmp/home/root# iptables -L -v -n
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 state INVALID
898 104K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 state NEW
252 14908 ACCEPT all -- br0 * 0.0.0.0/0 0.0.0.0/0 state NEW
15 5313 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp spt:67 dpt:68
1 148 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
220 8423 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 DROP all -- !br0 eth0 0.0.0.0/0 0.0.0.0/0
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 state INVALID
0 0 ACCEPT all -- br0 br0 0.0.0.0/0 0.0.0.0/0
0 0 DROP icmp -- eth0 * 0.0.0.0/0 0.0.0.0/0
0 0 DROP tcp -- br0 eth0 218.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 117.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 76.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 27.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 112.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 118.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 219.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 220.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
0 0 DROP tcp -- br0 eth0 2.0.0.0/8 192.168.1.13 1 tcp flags:0x3F/0x3F
8 508 ACCEPT all -- br0 eth0 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate DNAT
0 0 ACCEPT all -- br0 * 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT 887 packets, 284K bytes)
pkts bytes target prot opt in out source destination
Chain FUPNP (0 references)
pkts bytes target prot opt in out source destination
Chain PControls (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0
Chain logaccept (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 state NEW LOG flags 7 level 4 prefix `ACCEPT '
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0
Chain logdrop (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 state NEW LOG flags 7 level 4 prefix `DROP'
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
admin@RT-AC66U:/tmp/home/root# cat /tmp/ipt_filter.rules
cat: can't open '/tmp/ipt_filter.rules': No such file or directory
admin@RT-AC66U:/tmp/home/root# nvram get productid
RT-AC66U
admin@RT-AC66U:/tmp/home/root#
I take it that to run your script from earlier and to get cat /tmp/ipt_filter.rules I have to enable JFFS?
Mind you, I don't know Linux commands, yet, and my kids call me old at 39, so...