firewall.sh и вывод команды
root@debian:~# iptables -L -n -v
Chain INPUT (policy ACCEPT 8032 packets, 1698K bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 192.168.100.21 0.0.0.0/0
203 27139 ACCEPT all -- * * 192.168.100.23 0.0.0.0/0
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 192.168.100.21 0.0.0.0/0
0 0 ACCEPT all -- * * 0.0.0.0/0 192.168.100. 21
3180 232K ACCEPT all -- * * 192.168.100.23 0.0.0.0/0
0 0 ACCEPT all -- * * 0.0.0.0/0 192.168.100. 23
Chain OUTPUT (policy ACCEPT 1661 packets, 1123K bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 0.0.0.0/0 192.168.100. 21
25 7920 ACCEPT all -- * * 0.0.0.0/0 192.168.100. 23
Еще можно посмотреть вывод
root@debian:~# iptables-save | grep "192.168.100.23"
-A FORWARD -d 192.168.100.23/32 -j MARK --set-xmark 0x65/0xffffffff
-A FORWARD -s 192.168.100.23/32 -j MARK --set-xmark 0x1005/0xffffffff
-A INPUT -s 192.168.100.23/32 -j ACCEPT
-A FORWARD -s 192.168.100.23/32 -j ACCEPT
-A FORWARD -d 192.168.100.23/32 -j ACCEPT
-A OUTPUT -d 192.168.100.23/32 -j ACCEPT
У Вас используется авторизатор или установлен АО для абонентов ?
2012-11-22 12:54:26 -- Stg v. 2.407-p1
2012-11-22 12:54:26 -- Message queue created successfully. msgKey=5555 msgID=32768
2012-11-22 12:54:26 -- Timer thread started successfully.
2012-11-22 12:54:26 -- Storage plugin: mysql_store v.0.67. Loading successfull.
2012-11-22 12:54:26 -- Users started successfully.
2012-11-22 12:54:26 -- Traffcounter started successfully.
2012-11-22 12:54:26 -- Module: 'CAP_NF v. 0.4'. Start successfull.
2012-11-22 12:54:26 -- Module: 'Remote script v 0.3'. Start successfull.
2012-11-22 12:54:26 -- Module: 'InetAccess authorization plugin v.1.4'. Start successfull.
2012-11-22 12:54:26 -- Module: 'Always Online authorizator v.1.0'. Start successfull.
2012-11-22 12:54:26 -- Module: 'Stg configurator v.0.08'. Start successfull.
2012-11-22 12:54:26 -- Module: 'Stargazer RPC v. 0.2'. Start successfull.
2012-11-22 12:54:26 -- Stg started successfully.
2012-11-22 12:54:26 -- +++++++++++++++++++++++++++++++++++++++++++++
судя по всему авторизатор..