试了还是不行

[root@linux root]# iptables -A INPUT -i eth0 -p tcp --dport 23 -j ACCEPT
[root@linux root]# iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
RH-Lokkit-0-50-INPUT all -- anywhere anywhere
ACCEPT tcp -- anywhere anywhere tcp dpt:telnet
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain RH-Lokkit-0-50-INPUT (1 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT udp -- dns.sn.cninfo.net anywhere udp spt:domain
REJECT tcp -- anywhere anywhere tcp flags:SYN,RST,AC
K/SYN reject-with icmp-port-unreachable
REJECT udp -- anywhere anywhere udp reject-with icmp
-port-unreachable
ACCEPT tcp -- anywhere anywhere tcp dpts:0:1023 flag
s:SYN,RST,ACK/SYN
ACCEPT tcp -- anywhere anywhere tcp dpts:0:1023
[root@linux root]#