Changing TTL in AR750S longtime

Technical Support for Routers
1

Hey together,
I used to have a rule in my firewall (firmware 3.xx) that I set up via Luci: iptables -t mangle -I POSTROUTING 1 -j TTL --ttl-set 65, and it worked great.

Now, my AR750S is running firmware 4.3.25, and unfortunately, it's no longer possible to easily add rules through Luci (as far as I know).

What does work is when I access the command prompt via SSH (root@192.168.8.1) and set the rule iptables -t mangle -A POSTROUTING -o wlan-sta0 -j TTL --ttl-set 65.

I can also save the rule here with echo 'iptables -t mangle -A POSTROUTING -o wlan-sta0 -j TTL --ttl-set 65' >> /etc/firewall.user and see it with iptables -t mangle -L POSTROUTING -v -n.

The problem I'm facing now is that the rule disappears every time I reboot the AR750S. How can I save the rule so that it remains active after a restart?

I would be really grateful for any help!

2

Create file /etc/firewall-portal.user

clear_rules() {
    local ipt=$1
    local chain=$2
    local nums cnt

    nums=$($ipt -n -t mangle -L $chain --line-numbers | grep PORTAL_TTL | awk '{print $1}')
    cnt=$(echo $nums | wc -w)

    while [ $cnt -gt 0 ];
    do
        $ipt -t mangle -D $chain $cnt
        let cnt=cnt-1
    done
}

clear_rules iptables POSTROUTING
clear_rules iptables PREROUTING

iptables -t mangle -N PORTAL_TTL 2>/dev/null
iptables -t mangle -F PORTAL_TTL

[ -f /usr/sbin/ip6tables ] && {
    clear_rules ip6tables POSTROUTING
    clear_rules ip6tables PREROUTING

    ip6tables -t mangle -N PORTAL_TTL 2>/dev/null
    ip6tables -t mangle -F PORTAL_TTL
}
iptables -t mangle -A PORTAL_TTL -j TTL --ttl-set 65
iptables -t mangle -A POSTROUTING -o wlan-sta0 -j PORTAL_TTL

Then execute these commands:

uci set firewall.portal_ttl=include
uci set firewall.portal_ttl.path='/etc/firewall-portal.user'
uci set firewall.portal_ttl.reload='1'
/etc/init.d/firewall reload