Redirect traffic from 127.0.0.1 to 127.0.0.1 on port 53 to port 5300 with iptables

Posted by Zagorax on Server Fault See other posts from Server Fault or by Zagorax
Published on 2012-06-22T20:58:31Z Indexed on 2012/06/23 9:19 UTC
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iptables

I'm running a local dns server on port 5300 to develop a software. I need my machine to use that dns but I wasn't able to tell /etc/resolv.conf to check on a different port. I searched a bit on google and I didn't find a solution.

I set 127.0.0.1 as nameserver on /etc/resolv.conf. This is my whole /etc/resolv.conf:

nameserver 127.0.0.1

Could you please tell me how can I redirect outbound traffic on port 53 to another port?

I tried the following but it didn't work:

iptables -t nat -A PREROUTING -p tcp --dport 53 -j DNAT --to 127.0.0.1:5300 iptables -t nat -A PREROUTING -p udp --dport 53 -j DNAT --to 127.0.0.1:5300

Here is the output of iptables -t nat -L -v -n (with suggested rules):

Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 REDIRECT   tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp dpt:53 redir ports 5300 
    0     0 REDIRECT   udp  --  *      *       0.0.0.0/0            0.0.0.0/0           udp dpt:53 redir ports 5300 

Chain POSTROUTING (policy ACCEPT 302 packets, 19213 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 302 packets, 19213 bytes)
 pkts bytes target     prot opt in     out     source               destination

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