Eu tenho iptables-persistent e netfilter-persistent instalado:
$ dpkg -l '*-persistent'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-============================================-===========================-===========================-==============================================================================================
ii iptables-persistent 1.0.4 all boot-time loader for netfilter rules, iptables plugin
ii netfilter-persistent 1.0.4 all boot-time loader for netfilter configuration
Eu também tenho as regras salvas em /etc/iptables/rules.v4 (eu só me importo com o IPv4 por enquanto):
$ cat /etc/iptables/rules.v4
# Generated by iptables-save v1.6.0 on Fri Jan 19 09:49:17 2018
*security
:INPUT ACCEPT [11740:1271860]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [9784:2123999]
COMMIT
# Completed on Fri Jan 19 09:49:17 2018
# Generated by iptables-save v1.6.0 on Fri Jan 19 09:49:17 2018
*raw
:PREROUTING ACCEPT [18262:1677349]
:OUTPUT ACCEPT [9784:2123999]
COMMIT
# Completed on Fri Jan 19 09:49:17 2018
# Generated by iptables-save v1.6.0 on Fri Jan 19 09:49:17 2018
*nat
:PREROUTING ACCEPT [7367:452849]
:INPUT ACCEPT [872:48764]
:OUTPUT ACCEPT [500:37441]
:POSTROUTING ACCEPT [500:37441]
COMMIT
# Completed on Fri Jan 19 09:49:17 2018
# Generated by iptables-save v1.6.0 on Fri Jan 19 09:49:17 2018
*mangle
:PREROUTING ACCEPT [18262:1677349]
:INPUT ACCEPT [18259:1677229]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [9784:2123999]
:POSTROUTING ACCEPT [9784:2123999]
COMMIT
# Completed on Fri Jan 19 09:49:17 2018
# Generated by iptables-save v1.6.0 on Fri Jan 19 09:49:17 2018
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT --reject-with icmp-port-unreachable
-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 443 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m multiport --dports 25,587,465
-A INPUT -p tcp -m state --state NEW -m multiport --dports 110,995
-A INPUT -p tcp -m state --state NEW -m multiport --dports 143,993
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m multiport --dports 3721:3725 -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT
-A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7
-A INPUT -j DROP
-A FORWARD -j DROP
-A OUTPUT -j ACCEPT
COMMIT
# Completed on Fri Jan 19 09:49:17 2018
A regra que me interessa é a que vai para o final:
-A INPUT -p tcp -m state --state NEW -m multiport --dports 3721:3725 -j ACCEPT
No entanto, quando reinicializo o servidor, não obtenho essa regra:
$ sudo iptables -4 -L
[sudo] password for kal:
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere
REJECT all -- anywhere 127.0.0.0/8 reject-with icmp-port-unreachable
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ACCEPT tcp -- anywhere anywhere tcp dpt:http
ACCEPT tcp -- anywhere anywhere tcp dpt:https
tcp -- anywhere anywhere state NEW multiport dports smtp,submission,urd
tcp -- anywhere anywhere state NEW multiport dports pop3,pop3s
tcp -- anywhere anywhere state NEW multiport dports imap2,imaps
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh
ACCEPT icmp -- anywhere anywhere icmp echo-request
LOG all -- anywhere anywhere limit: avg 5/min burst 5 LOG level debug prefix "iptables denied: "
DROP all -- anywhere anywhere
Chain FORWARD (policy ACCEPT)
target prot opt source destination
DROP all -- anywhere anywhere
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere
Chain f2b-shadowsocks (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere
Chain f2b-sshd (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere
Observe também que o iptables tem algumas regras que estavam presentes antes mesmo de eu instalar iptables-persistent e netfilter-persistent - por exemplo, os para http, smtp, pop3, imap, ssh. Eu não tenho ideia de onde eles vêm. Claro, eu tenho o openssh e o nginx instalados e seus serviços habilitados, mas eu nunca adicionei as regras do iptables para eles.
Se eu olhar para a saída do journalctl, o netfilter-persistent.service foi iniciado com êxito:
$ sudo journalctl -xu netfilter-persistent.service
-- Logs begin at Fri 2018-01-19 18:55:13 HKT, end at Fri 2018-01-19 19:05:41 HKT. --
Jan 19 18:55:13 yuma systemd[1]: Starting netfilter persistent configuration...
-- Subject: Unit netfilter-persistent.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit netfilter-persistent.service has begun starting up.
Jan 19 18:55:13 yuma netfilter-persistent[1997]: run-parts: executing /usr/share/netfilter-persistent/plugins.d/15-ip4tables start
Jan 19 18:55:14 yuma netfilter-persistent[1997]: run-parts: executing /usr/share/netfilter-persistent/plugins.d/25-ip6tables start
Jan 19 18:55:14 yuma systemd[1]: Started netfilter persistent configuration.
-- Subject: Unit netfilter-persistent.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit netfilter-persistent.service has finished starting up.
--
-- The start-up result is done.
Se eu reiniciar manualmente netfilter-persistent.service após a inicialização completa da máquina, obtenho a regra que desejo:
$ sudo iptables -4 -L
[...]
ACCEPT tcp -- anywhere anywhere state NEW multiport dports 3721:3725
[...]
Então, por que o netfilter-persistent não funciona na inicialização?
Alguma coisa está sobrescrevendo completamente o iptables depois de netfilter-persistent ?
O que posso fazer sobre isso?
UPDATE
Eu também não tenho ufw ou firewalld .