multicast and firewall, Please help!
 

Hi! Could someone pass me the syntax to enable certain(or all) multicast address in iptables?

I have a program does multicast, it runs well only if I shut down my firewall.

I am using Fedora 9.

Thanks in advance!

Hi qspares,

You could try something like:

iptables -A INPUT -m addrtype --src-type MULTICAST -j ACCEPT


cheers,

kbp

Tried it, but doesn't seem to work, also tried dst-type, still doesn't work.
As soon as I shut the firewall off, I immediately got the multicast packages

:(

Could you post the whole iptables config please qspares?

'iptables -L'

thanks

Here it is:

rt@sun#/>iptables -A INPUT -m addrtype --src-type MULTICAST -j ACCEPT
rt@sun#/>iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination
DROP all -- softbank220000000000.bbtec.net/6 anywhere
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT icmp -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:yo-main
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:domain
ACCEPT udp -- anywhere anywhere state NEW udp dpt:domain
ACCEPT udp -- anywhere anywhere state NEW udp dpt:netbios-ns
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
ACCEPT all -- anywhere anywhere ADDRTYPE match src-type MULTICAST

Chain FORWARD (policy ACCEPT)
target prot opt source destination
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target prot opt source destination
rt@sun#/>

Hi qspares,

I see the problem, you have a 'reject all' line, you will need to insert the multicast line before this one.

Use 'iptables -L --line-numbers' to display the line number of each rule then change:

iptables -A INPUT -m addrtype --src-type MULTICAST -j ACCEPT

to

iptables -I INPUT rule_number -m addrtype --src-type MULTICAST -j ACCEPT

where rule_number is the line before the 'reject all' line

cheers,

kbp