run the following command:-

# iptables -t nat -A PREROUTING -d 212.241.215.114 -p tcp --dport 26 -j REDIRECT --to-ports 25 -v

REDIRECT  tcp opt -- in * out *  0.0.0.0/0  -> 212.241.215.114  tcp dpt:26 redir ports 25
iptables: No chain/target/match by that name

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# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     icmp --  anywhere             anywhere
VZ_INPUT   all  --  anywhere             anywhere

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
ACCEPT     icmp --  anywhere             anywhere
VZ_FORWARD  all  --  anywhere             anywhere

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     icmp --  anywhere             anywhere
VZ_OUTPUT  all  --  anywhere             anywhere

Chain VZ_FORWARD (1 references)
target     prot opt source               destination

Chain VZ_INPUT (1 references)
target     prot opt source               destination

Chain VZ_OUTPUT (1 references)
target     prot opt source               destination


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# iptables -L -n -t nat
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination