[Serusers] Protecting a SER server

[Andrei Pelinescu-Onciul]

On May 11, 2004 at 16:28, Olivier <olivier at siteboulevard.com> wrote:
> Hi,
>  
> What is the best method to protect a RedHat Linux box against attack
> while running a SER server.
>  
> What is the impact of using iptables filtering on SER ? Any advices ?

Use only udp and filter everything you want. Just make sure you allow
udp port 5060 (or wahtever port you are running ser on). All udp
messages sent by ser will haver source port==5060, and all incoming udp
should have dest. port == 5060.

tcp is more complicated to filter. You could allow incoming connections
only on 5060, but you can't filter outgoing traffic (the source port is
 dynamically allocated). Also the source ip of the tcp connections initiated
 by ser depends on the routing table on multihomed host.

Andrei