Use PF (Packet Filter) on iOs ?

[thx51]

Hi everybody,

 

I have freshly set up an L2TP ipsec server, but I was disappointed when I realize that my network administrator filter several critical ports. So i'm not able to establish an ipsec connection with my iphone on defaults ports 4500, 1701, etc.

 

My first reaction was "Hey, what about changing the defaults ports to 80, 443 or 21 ?" But actually it was impossible because these ports was hard defined at the compilation. I tried to change it with an hex editor, but I encounter several problems with the vpn client sandbox.

 

So the next idea consists of forwarding these ports with Packet Filter. But i'm not very familiar with PF, i'm used to play with iptables. I just have to write several rules to change the destination ports of my packets :

 

For example, all packets that have a destination port like 4500, must be forwarded to 443.

 

Thanks in advance for any help !