First, I love Fedora 20. :) I'm newcomers from Debian/Ubuntu/Suse, but I real like this clean distro.

But I found some problems, and can't move forward with this little things.

I have 2 PC in home network, both under Fedora (Gnome and LXDE edition).

On "main" PC, who's role is gate to external network, I need run command for sync MTU between interfaces/networks:

iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

I can't found modern replace for this old-school command. All other commands for network like masquerading and change active zone I save by

firewall-cmd bla-bla-bla --permanent

So, one command who's must run at startup system is above "iptables ..". Ok.

For this I create new file:

$ cat /usr/lib/systemd/system/setup-mtu.service
Description=Настройка MTU на шлюзе для нормальной работы инета в домашней сети

ExecStart=/usr/sbin/iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu


Enable this service. And have good status after reboot:

$ sudo systemctl status setup-mtu.service
setup-mtu.service - Настройка MTU на шлюзе для нормальной работы инета в домашней сети
   Loaded: loaded (/usr/lib/systemd/system/setup-mtu.service; enabled)
   Active: inactive (dead) since Пн 2014-01-27 16:18:06 MSK; 7h ago
  Process: 22933 ExecStart=/usr/sbin/iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu (code=exited, status=0/SUCCESS)

янв 27 16:18:06 localhost.localdomain systemd[1]: Started Настройка MTU на шлюзе д...и.
Hint: Some lines were ellipsized, use -l to show in full.

But in real, I need manual run this command every time after reboot PC. The same problem was happens with other network commands. So I passed this problem with firewall-cmd ... --permanent command. Until MTU sync. :((

I need your help!

Why network setting don't real apply at startup scripts with service?

  • Why are you making your own service for iptables when fedora already has one? – jordanm Jan 28 '14 at 4:41
  • Please, give me more information what you meanings! – user42104 Jan 28 '14 at 6:19

Problem is SOLVED.

I found new-style command for MTU sync:

sudo firewall-cmd --permanent --direct --add-passthrough ipv4 -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

Also problem was in too early running of service. After that was running firewalld and flush all rules.

Now, with permanent one-run command above all work perfectly!

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