De acordo com as informações que você postou, não deve ser bloqueado.
Para depurar o iptables
insira uma regra com TRACE
target em raw
table:
TRACE
This target marks packets so that the kernel will log every rule which match the packets as those traverse the tables, chains, rules.
A logging backend, such as ip(6)t_LOG or nfnetlink_log, must be loaded for this to be visible. The packets are logged with the string prefix: "TRACE: tablename:chainname:type:rulenum " where type can be "rule" for plain rule, "return" for implicit rule at the end of a user defined chain and "policy" for the policy of the built in chains. It can only be used in the raw table.
então, no seu caso:
modprobe nfnetlink_log
iptables -t raw -I PREROUTING -s 197.245.0.0/16 -p tcp --dport 5061 -j TRACE
Quando terminar a análise, remova-a:
iptables -t raw -D PREROUTING -s 197.245.0.0/16 -p tcp --dport 5061 -j TRACE
Use o comando iptables
para fazer isso, não os comandos firewall-*
.