0.6.5

Stop judging xt_comment by lsmod, which wasn't reliable
Users who want to disable iptables comment should set env var

NOTICE

@@ -1,42 +0,0 @@
-Copyright (c) 2013, oblique
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-* Redistributions of source code must retain the above copyright notice, this
-  list of conditions and the following disclaimer.
-
-* Redistributions in binary form must reproduce the above copyright notice,
-  this list of conditions and the following disclaimer in the documentation
-  and/or other materials provided with the distribution.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-================================================================================
-
-linux-router
-Copyright (C) 2018  garywill
-
-This library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Lesser General Public
-License as published by the Free Software Foundation; either
-version 2.1 of the License, or (at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Lesser General Public License for more details.
-
-You should have received a copy of the GNU Lesser General Public
-License along with this library; if not, write to the Free Software
-Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

README.md

@@ -4,8 +4,7 @@ Set Linux as router in one command. Able to Provide Internet, or create Wifi hot
 
 It wraps `iptables`, `dnsmasq` etc. stuff. Use in one command, restore in one command or by `control-c` (or even by closing terminal window).
 
-[Buy me a coffee](https://github.com/garywill/receiving/blob/master/receiving_methods.md)
+[More tools and projects 🛠️](https://garywill.github.io) | [🍻 Buy me a coffee ❤️](https://github.com/garywill/receiving/blob/master/receiving_methods.md)
-
 
 ## Features
 
@@ -13,15 +12,16 @@ Basic features:
 
 - Create a NATed sub-network
 - Provide Internet
-- DHCP server and RA
+- DHCP server (and RA) + DNS server
-- DNS server 
+  - Configuring what DNS the DHCP server offers to clients
+  - Configuring upstream DNS for local DNS server (kind of a DNS proxy)
 - IPv6 (behind NATed LAN, like IPv4)
 - Creating Wifi hotspot:
   - Channel selecting
   - Choose encryptions: WPA2/WPA, WPA2, WPA, No encryption
-  - Create AP on the same interface you are getting Internet (require same channel)
+  - Create AP on the same interface you are getting Internet (usually require same channel)
 - Transparent proxy (redsocks)
-- DNS proxy
+- Transparent DNS proxy (hijack port 53 packets)
 - Compatible with NetworkManager (automatically set interface as unmanaged)
 
 **For many other features, see below [CLI usage](#cli-usage-and-other-features)**
@@ -67,12 +67,7 @@ Internet----(eth0/wlan0)-Linux-(virtual interface)-----VM/container
 sudo lnxrouter -i eth1
 ```
 
-### Provide an interface's Internet to another interface
+no matter which interface (other than `eth1`) you're getting Internet from.
-
-```
-sudo lnxrouter -i eth1 -o vpn0 --dhcp-dns 1.1.1.1 -6 --dhcp-dns6 [2606:4700:4700::1111]
-```
-> Read _Notice 1_
 
 ### Create Wifi hotspot
 
@@ -80,8 +75,31 @@ sudo lnxrouter -i eth1 -o vpn0 --dhcp-dns 1.1.1.1 -6 --dhcp-dns6 [2606:4700:4700
 sudo lnxrouter --ap wlan0 MyAccessPoint -p MyPassPhrase
 ```
 
+no matter which interface you're getting Internet from (even from `wlan0`). Will create virtual Interface `x0wlan0` for hotspot.
+
+### Provide an interface's Internet to another interface
+
+Clients access Internet through only `isp5`
+
+<details>
+
+```
+sudo lnxrouter -i eth1 -o isp5  --no-dns  --dhcp-dns 1.1.1.1  -6 --dhcp-dns6 [2606:4700:4700::1111]
+```
+
+> In this case of usage, it's recommended to:
+> 
+> 1. Stop serving local DNS
+> 2. Tell clients which DNS to use (ISP5's DNS. Or, a safe public DNS, like above example)
+
+> Also, read *Notice 1*
+
+</details>
+
 ### LAN without Internet
 
+<details>
+
 ```
 sudo lnxrouter -n -i eth1
 sudo lnxrouter -n --ap wlan0 MyAccessPoint -p MyPassPhrase
@@ -89,9 +107,12 @@ sudo lnxrouter -n --ap wlan0 MyAccessPoint -p MyPassPhrase
 
 > Read _Notice 1_
 
+</details>
 
 ### Internet for LXC
 
+<details>
+
 Create a bridge
 
 ```
@@ -111,12 +132,16 @@ lxc.network.hwaddr = xx:xx:xx:xx:xx:xx
 sudo lnxrouter -i lxcbr5
 ```
 
+</details>
+
 ### Transparent proxy
 
-For example through Tor
+All clients' Internet traffic go through, for example, Tor
+
+<details>
 
 ```
-sudo lnxrouter -i eth1 --tp 9040 --dns 9053 -g 192.168.55.1 --p6 fd00:5:6:7::
+sudo lnxrouter -i eth1 --tp 9040 --dns 9053 -g 192.168.55.1 -6 --p6 fd00:5:6:7::
 ```
 
 In `torrc`
@@ -128,10 +153,14 @@ TransPort [fd00:5:6:7::1]:9040
 DNSPort [fd00:5:6:7::1]:9053
 ```
 
+</details>
+
 ### Clients-in-sandbox network
 
 To not give our infomation to clients. Clients can still access Internet.
 
+<details>
+
 ```
 sudo lnxrouter -i eth1 \
     --tp 9040 --dns 9053 \
@@ -140,11 +169,14 @@ sudo lnxrouter -i eth1 \
     --catch-dns --log-dns   # optional
 ```
 
-> This script comes with no warrenty, use on your own risk
+</details>
 
+> This script comes with no warrenty. Use on your own risk
 
 ### Use as transparent proxy for LXD
 
+<details>
+
 Create a bridge
 
 ```
@@ -195,16 +227,24 @@ To remove the customized `eth0` to restore default `eth0`
 lxc config device remove <container> eth0
 ```
 
+</details>
+
 ### Use as transparent proxy for VirtualBox
 
+<details>
+
 In VirtualBox's global settings, create a host-only network `vboxnet5` with DHCP disabled.
 
 ```
 sudo lnxrouter -i vboxnet5 --tp 9040 --dns 9053
 ```
 
+</details>
+
 ### Use as transparent proxy for firejail
 
+<details>
+
 Create a bridge
 
 ```
@@ -213,11 +253,15 @@ sudo brctl addbr firejail5
 
 ```
 sudo lnxrouter -i firejail5 -g 192.168.55.1 --tp 9040 --dns 9053 
-firejail --net=firejail5 --dns=192.168.55.1 --blacklist=/var/run/nscd
+firejail --net=firejail5 --dns=192.168.55.1 --blacklist=/var/run/nscd  # nscd is cache service, which shouldn't be accessed in jail here
 ```
 
+</details>
+
 ### CLI usage and other features
 
+<details>
+
 ```
 Usage: lnxrouter <options>
 
@@ -229,6 +273,7 @@ Options:
                             and to provide Internet to
                             (To create Wifi hotspot use '--ap' instead)
     -o <interface>          Specify an inteface to provide Internet from.
+                            (See Notice 1)
                             (Note using this with default DNS option may leak
                             queries to other interfaces)
     -n                      Do not provide Internet (See Notice 1)
@@ -253,13 +298,14 @@ Options:
     --no-dnsmasq            Disable dnsmasq server (DHCP, DNS, RA)
     --catch-dns             Transparent DNS proxy, redirect packets(TCP/UDP) 
                             whose destination port is 53 to this host
-    --log-dns               Show DNS query log
+    --log-dns               Show DNS query log (dnsmasq)
     --dhcp-dns <IP1[,IP2]>|no
-                            Set IPv4 DNS offered by DHCP (default: this host)
+                            Set IPv4 DNS offered by DHCP (default: this host).
     --dhcp-dns6 <IP1[,IP2]>|no
                             Set IPv6 DNS offered by DHCP (RA) 
                             (default: this host)
                             (Note IPv6 addresses need '[]' around)
+                            Using both above two will enable '--no-dns' 
     --hostname <name>       DNS server associate this name with this host.
                             Use '-' to read name from /etc/hostname
     -d                      DNS server will take into account /etc/hosts
@@ -316,7 +362,15 @@ Options:
     --stop <id>             Stop a running instance
         For <id> you can use PID or subnet interface name.
         You can get them with '--list-running'
+```
 
+</details>
+
+## Notice
+
+<details>
+
+```
     Notice 1:   This script assume your host's default policy won't forward
                 packets, so the script won't explictly ban forwarding in any
                 mode. In some unexpected case may cause unwanted packets 
@@ -324,13 +378,18 @@ Options:
                 want isolated network
 ```
 
-> These changes to system will not be restored by script's cleanup:
+</details>
-> 1. `/proc/sys/net/ipv4/ip_forward = 1` and `/proc/sys/net/ipv6/conf/all/forwarding = 1`
-> 1. dnsmasq in Apparmor complain mode
-> 1. Kernel module `nf_nat_pptp` loaded
-> 1. The wifi device which is used to create hotspot is `rfkill unblock`ed
-> 1. Wifi country code, if user specified
 
+## What changes are done to Linux system
+
+On exit of a linux-router instance, script **will do cleanup**, i.e. undo most changes to system. Though, **some** changes will **not** be undone, which are:
+
+1. `/proc/sys/net/ipv4/ip_forward = 1` and `/proc/sys/net/ipv6/conf/all/forwarding = 1`
+2. dnsmasq (if used) in Apparmor complain mode
+3. hostapd (if used) in Apparmor complain mode
+4. Kernel module `nf_nat_pptp` loaded
+5. The wifi device which is used to create hotspot is `rfkill unblock`ed
+6. Wifi country code, if user specified
 
 ## Dependencies
 
@@ -338,37 +397,92 @@ Options:
 - procps or procps-ng
 - iproute2
 - dnsmasq
-- iptables (legacy. nft not tested)
+- iptables (or nftables with `iptables-nft` translation linked)
 - WiFi hotspot dependencies
-   - hostapd
+  - hostapd
-   - iw
+  - iw
-   - iwconfig (you only need this if 'iw' can not recognize your adapter)
+  - iwconfig (you only need this if 'iw' can not recognize your adapter)
-   - haveged (optional)
+  - haveged (optional)
-   - qrencode (optional)
+  - qrencode (optional)
 
 ## TODO
 
+<details>
+
 - WPA3
 - Global IPv6
 - Explictly ban forwarding if not needed
 - Bring bridging method back
 
-## Donate
+</details>
 
-[Buy me a coffee](https://github.com/garywill/receiving/blob/master/receiving_methods.md) , this project took me lots of time!
+## License
 
+linux-router is LGPL licensed
 
-[打赏一个](https://github.com/garywill/receiving/blob/master/receiving_methods.md) 
+<details>
 
-## For developers
+```
+linux-router
+Copyright (C) 2018  garywill
 
-**Many thanks to project [create_ap](https://github.com/oblique/create_ap)**.
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
 
-This script was forked from create\_ap. Now it's quite different from it. (See `history` branch for how I modified create_ap)
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
 
-There're some TO-DOs listed, at both above and in the code file. We'll appreciate your help.
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+```
 
-------------------
+</details>
 
-More of my projects: https://garywill.github.io
+Upstream create_ap was BSD licensed
 
+<details>
+
+```
+Copyright (c) 2013, oblique
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+```
+
+</details>
+
+## Meet developer(s) and become one of them
+
+Visit [**my homepage** 🏡](https://garywill.github.io) to see **more tools and projects** 🛠️.
+
+> [❤️ Buy me a coffee](https://github.com/garywill/receiving/blob/master/receiving_methods.md) , this project took me lots of time! ([❤️ 打赏一个!](https://github.com/garywill/receiving/blob/master/receiving_methods.md))
+> 
+> 🥂 ( ^\_^) o自自o (^_^ ) 🍻
+
+🤝 Bisides, thank [create_ap](https://github.com/oblique/create_ap) by [oblique](https://github.com/oblique). This script was forked from create\_ap. Now they are quite different. (See `history` branch for how I modified create_ap). 🤝 Also thank those who contributed to that project.
+
+👨‍💻 You can be contributor, too! 🍃 There're some TO-DOs listed, at both above and in the code file. Also some unfulfilled enhancements in the Issues. Your name can be here!

lnxrouter

@@ -1,7 +1,6 @@
 #!/bin/bash
 
-# TODO: showing version (or git commit) on running
+VERSION=0.6.5
-VERSION=0.6.2
 PROGNAME="$(basename $0)"
 
 export LC_ALL=C
@@ -9,10 +8,16 @@ export LC_ALL=C
 SCRIPT_UMASK=0122
 umask $SCRIPT_UMASK
 
+phead() {
+    echo "linux-router $VERSION (https://github.com/garywill/linux-router)"
+}
+phead2() {
+    echo "Released under LGPL, with no warranty. Use on your own risk."
+}
 usage() {
+    phead
+    phead2
     cat << EOF
-linux-router $VERSION (https://github.com/garywill/linux-router)
-Released under LGPL, with no warranty. Use on your own risk.
 
 Usage: $PROGNAME <options>
 
@@ -24,6 +29,7 @@ Options:
                             and to provide Internet to
                             (To create Wifi hotspot use '--ap' instead)
     -o <interface>          Specify an inteface to provide Internet from.
+                            (See Notice 1)
                             (Note using this with default DNS option may leak
                             queries to other interfaces)
     -n                      Do not provide Internet (See Notice 1)
@@ -48,13 +54,14 @@ Options:
     --no-dnsmasq            Disable dnsmasq server (DHCP, DNS, RA)
     --catch-dns             Transparent DNS proxy, redirect packets(TCP/UDP) 
                             whose destination port is 53 to this host
-    --log-dns               Show DNS query log
+    --log-dns               Show DNS query log (dnsmasq)
     --dhcp-dns <IP1[,IP2]>|no
-                            Set IPv4 DNS offered by DHCP (default: this host)
+                            Set IPv4 DNS offered by DHCP (default: this host).
     --dhcp-dns6 <IP1[,IP2]>|no
                             Set IPv6 DNS offered by DHCP (RA) 
                             (default: this host)
                             (Note IPv6 addresses need '[]' around)
+                            Using both above two will enable '--no-dns' 
     --hostname <name>       DNS server associate this name with this host.
                             Use '-' to read name from /etc/hostname
     -d                      DNS server will take into account /etc/hosts
@@ -120,7 +127,6 @@ Options:
                 
 Examples:
     $PROGNAME -i eth1
-    $PROGNAME --ap wlan0 MyAccessPoint
     $PROGNAME --ap wlan0 MyAccessPoint -p MyPassPhrase
     $PROGNAME -i eth1 --tp <transparent-proxy> --dns <dns-proxy>
 EOF
@@ -203,7 +209,6 @@ define_global_variables(){
     CONFDIR=
     NM_RUNNING=0
     NM_UNM_LIST=  # it's called "list" but for now one interface
-    XT_COMMENT=1
 }
 
 parse_user_options(){
@@ -812,21 +817,35 @@ nm_restore_manage() {
     fi
 }
 #=========
+check_iptables()
+{
+    echo
+    iptables --version
+    
+    if which firewall-cmd > /dev/null 2>&1; then
+        if [[ "$(firewall-cmd --state 2>&1)" == "running" ]]; then
+            echo "firewalld is running ($(firewall-cmd --version))"
+            echo -e "\nWARN: We haven't completed the compatibility with firewalld.\nWARN: If you see any trouble, try:\nWARN:     1) 'firewall-cmd --zone=trusted --add-interface=<SUBN_IFACE>'\nWARN:     2) disable firewalld\n" >&2 
+            # TODO
+        fi
+    fi
+}
 iptables_()
 {
-    if [[ $XT_COMMENT -eq 1 ]]; then
+    # NETFILTER_XT_MATCH_COMMENT would be a env variable if user wants to disable '-m comment'
-        iptables -w $@ -m comment --comment "lnxrouter-$$-$SUBNET_IFACE"
+    if [[ "$NETFILTER_XT_MATCH_COMMENT" == "0" ]]; then
-    else
         iptables -w $@ 
+    else
+        iptables -w $@ -m comment --comment "lnxrouter-$$-$SUBNET_IFACE"
     fi
     return $?
 }
 ip6tables_()
 {
-    if [[ $XT_COMMENT -eq 1 ]]; then
+    if [[ "$NETFILTER_XT_MATCH_COMMENT" == "0" ]]; then
-        ip6tables -w $@ -m comment --comment "lnxrouter-$$-$SUBNET_IFACE"
-    else
         ip6tables -w $@
+    else
+        ip6tables -w $@ -m comment --comment "lnxrouter-$$-$SUBNET_IFACE"
     fi
     return $?
 }
@@ -870,6 +889,7 @@ start_ban_lan() {
     echo
     echo "iptables: Disallow clients to access LAN"
     iptables_ -N BANLAN-f-${SUBNET_IFACE}  || die
+    # TODO: allow '--dhcp-dns(6)' address port 53, which can be something needed, e.g. a VPN's internal private IP
     iptables_ -v -I BANLAN-f-${SUBNET_IFACE} -d 0.0.0.0/8 -j REJECT || die # TODO: use array
     iptables_ -v -I BANLAN-f-${SUBNET_IFACE} -d 10.0.0.0/8 -j REJECT || die
     iptables_ -v -I BANLAN-f-${SUBNET_IFACE} -d 100.64.0.0/10 -j REJECT || die
@@ -885,7 +905,7 @@ start_ban_lan() {
     iptables_ -N BANLAN-i-${SUBNET_IFACE}
     #iptables_ -v -I BANLAN-i-${SUBNET_IFACE} -i ${SUBNET_IFACE} -j REJECT || die
     iptables_ -v -I BANLAN-i-${SUBNET_IFACE} -i ${SUBNET_IFACE} ! -p icmp -j REJECT || die
-    # TODO: ipv6 need icmp to function. maybe we can block some unneeded icmp to improve security
+    # ipv6 need icmp to function. TODO: maybe we can block some unneeded icmp to improve security
     
     iptables_ -I INPUT -i ${SUBNET_IFACE} -j BANLAN-i-${SUBNET_IFACE} || die
     
@@ -1136,7 +1156,7 @@ kill_processes() { # for this instance
             pn=$( ps -p $pid -o comm= ) 
             #echo "Killing $pid $pn ... "
             pkill -P $pid
-            kill $pid 2>/dev/null && ( echo "Killed $pid $pn" && rm $x ) || echo "Failed to kill $pid $pn, it may have exited"
+            kill $pid 2>/dev/null && ( echo "Killed $(basename $x) $pid $pn" && rm $x ) || echo "Failed to kill $(basename $x) $pid $pn, it may have exited"
         fi
     done
 }
@@ -1848,6 +1868,7 @@ run_wifi_ap_processes() {
         haveged_watchdog &
         HAVEGED_WATCHDOG_PID=$!
         echo "$HAVEGED_WATCHDOG_PID" > "$CONFDIR/haveged_watchdog.pid"
+        echo
         echo "haveged_watchdog PID: $HAVEGED_WATCHDOG_PID" 
     fi
 
@@ -1860,6 +1881,11 @@ run_wifi_ap_processes() {
     fi
     echo 
     echo "Starting hostapd"
+    
+    if which complain > /dev/null 2>&1; then
+        complain hostapd
+    fi
+    
     # hostapd '-P' works only when use '-B' (run in background)
     $STDBUF_PATH hostapd $HOSTAPD_DEBUG_ARGS -P "$CONFDIR/hostapd.pid" "$CONFDIR/hostapd.conf"  &
     HOSTAPD_PID=$!
@@ -1874,14 +1900,15 @@ run_wifi_ap_processes() {
 }
 
 start_dnsmasq() {
+    echo 
+    echo "Starting dnsmasq"
+    
     if which complain > /dev/null 2>&1; then
         # openSUSE's apparmor does not allow dnsmasq to read files.
         # remove restriction.
         complain dnsmasq
     fi
     
-    echo 
-    echo "Starting dnsmasq"
     # Using '-d'(no daemon) dnsmasq will not turn into 'nobody'
     # '-x' works only when no '-d'
     dnsmasq  -k -C "$CONFDIR/dnsmasq.conf" -x "$CONFDIR/dnsmasq.pid" -l "$CONFDIR/dnsmasq.leases" & 
@@ -1943,6 +1970,10 @@ daemonizing_check
 
 ## ===== Above don't echo anything if no warning or error====================
 ## ========================================================
+phead
+phead2
+echo
+
 echo "PID: $$"
 
 TARGET_IFACE="$(decide_target_interface)" || exit 1 # judge wired (-i CONN_IFACE) or wireless hotspot (--ap $WIFI_IFACE)
@@ -2024,16 +2055,6 @@ if [[ $IPV6 -eq 1 ]] ; then
     ip -6 addr add ${GATEWAY6}/64  dev ${SUBNET_IFACE} || die "Failed setting ${SUBNET_IFACE} IPv6 address"
 fi
 
-function check_iptables() {
-    if iptables --version | grep "nf_tables" >/dev/null 2>&1 ; then
-        echo -e "\nWARN: Your system is using nftables. This script is tested with iptables legacy only. If you encounter problems, visit following URL for infomation:\n  https://github.com/oblique/create_ap/issues/373\n  https://github.com/oblique/create_ap/issues/433\n  https://github.com/garywill/linux-router/issues/18\n" >&2
-    fi
-    
-    if ! lsmod | grep -E "\bxt_comment\b" >/dev/null 2>&1 ; then
-        XT_COMMENT=0
-    fi
-}
-
 check_iptables
 
 # enable Internet sharing
@@ -2045,7 +2066,7 @@ if [[ "$SHARE_METHOD" == "none" ]]; then
     
 elif [[ "$SHARE_METHOD" == "nat" ]]; then
 
-    [[ "$INTERNET_IFACE" && "$dnsmasq_NO_DNS" -eq 0 ]] && echo -e "\nWARN: You specified Internet interface but this host is providing local DNS, queries may leak to other interfaces!!!\n" >&2
+    [[ "$INTERNET_IFACE" && "$dnsmasq_NO_DNS" -eq 0 ]] && echo -e "\nWARN: You specified Internet interface but this host is providing local DNS. In some unexpected case (eg. mistaken configurations), queries may leak to other interfaces, which you should be aware of.\n" >&2
     
     start_nat
     
@@ -2067,7 +2088,7 @@ elif [[ "$SHARE_METHOD" == "redsocks" ]]; then
         echo 1 > "/proc/sys/net/ipv6/conf/$SUBNET_IFACE/forwarding" || die "Failed enabling $SUBNET_IFACE ipv6 forwarding" # to set NA router bit
     fi
     
-    [[ "$dnsmasq_NO_DNS" -eq 0 && ! $DNS ]] &&  echo -e "\nWARN: You are using in transparent proxy mode but this host is providing local DNS, this may cause privacy leak !!!\n" >&2
+    [[ "$dnsmasq_NO_DNS" -eq 0 && ! $DNS ]] &&  echo -e "\nWARN: You are using in transparent proxy mode but this host is providing local DNS. In some unexpected case (eg. mistaken configurations), queries may leak to other interfaces, which you should be aware of.\n" >&2
 
     [[ "$BANLAN" -eq 1 ]] && start_ban_lan