REDIRECT a port in ip6tables

Question

How can I redirect one port to another local port by using ip6tables ? e.g. something like this : ip6tables -t nat -A PREROUTING -j REDIRECT -p tcp --dport 443 --to-ports 8443

Answer 1

ip6tables does not support REDIRECT. (Normally people use this in a NAT environment, and NAT is generally not supported with IPv6.)

If all you need to do is bind to the low port as a normal user, why not try the workaround described in this answer? Of course, in the case of Tomcat, it sounds like this would mean giving any Java process that capability.

Answer 2

Well this is an old question, but since I need to do the same thing… Here is what I've found:

TPROXY

This target is only valid in the mangle table, in the PREROUTING chain and user-defined chains which are only called from this chain. It redirects the packet to a local socket without changing the packet header in any way. It can also change the mark value which can then be used in advanced routing rules. It takes three options:
--on-port port
    This specifies a destination port to use. It is a required option, 0 means the new destination port is the same as the original. This is only valid if the rule also specifies -p tcp or -p udp. 
--on-ip address
    This specifies a destination address to use. By default the address is the IP address of the incoming interface. This is only valid if the rule also specifies -p tcp or -p udp. 
--tproxy-mark value[/mask]
    Marks packets with the given value/mask. The fwmark value set here can be used by advanced routing. (Required for transparent proxying to work: otherwise these packets will get forwarded, which is probably not what you want.)

This is valid for ip6tables only, of course. So I guess that this is valid:

ip6tables -t mangle -A PREROUTING -p tcp --dport 443 -j TPROXY --on-port 8443

However, I didn't try it yet.