Linksys AC Series Router Configuration Tips for OpenWRT: Difference between revisions

As it started out, this article was intended to be a quick how to on a couple of items, but then grew to enormous proportions.  There was some consideration on breaking it into smaller sections, but the Mediawiki interface with its table of contents mitigates that need to an acceptable level.

Because this article contains a lot of information in addition to "How to..." tutorials, this sections summarizes and provides links to the major "How to..." sections below.

*Partition and Configure OpenWRT to use external storage drives, not just for storage, but also as a replacement / addition to the internal non-volitile storage

*The fourth time you turn the power switch on you can let the device boot and it should boot into the other partition.

===Upgrading the "Other Partition" from OpenWRT (be it another OpenWRT installation, Linksys firmware, DD-WRT, etc.)===

==OpenWRT System Logging==

===Recommended Hardware Devices===

Others have the USB 3.0 speeds measured considerably slower at about 20 MB/S: https://www.kitguru.net/peripherals/james-morris/linksys-wrt3200acm-ac3200-wireless-router-review/4/

Anyway, the above mentioned SanDisk device tops out at about 70 MB/S on every system that the above mentioned Patriot device tops out at over 200 MB/S.  Notice that 70 MB/S speed mentioned twice?  Once for the SanDisk device and once for the AC Series.  The next item to consider is price.  The SanDisk is not the cheapest, but it is fairly low.  When price and performance are both considered, it turns out the SanDisk device beats everyone.  And since the AC series router and SanDisk USB Flash Drive both top out at around 70 MB/S, that makes it the perfect match.

But there is a solution...  A USB 3.0 A Male to A Female Adapter (Part # 1206-N, UPC 848076012233) from a company named CMPLE.  It is available from several places: [https://www.walmart.com/ip/Cmple-USB-3-0-A-Male-to-A-Female-Adapter/172246645 Wal-Mart], [https://www.ebay.com/itm/NEW-USB-3-0-A-MALE-TO-A-FEMALE-M-F-ADAPTER-CONNECTOR-NEW-/362695174727 eBAy], and from the company that appears to have it manufactured (in China), [https://www.cmple.com/ProductsBySKU/1206-N CMPLE].  Even at about $3.00 it is a bit more expensive than other similar products (and there are only a few).  But it has one advantage in that the orientation of the male and female part of the connector are arranged such that the above noted 3 Port USB 3.0 hub from Sabrent can connect and be in the "up" position.  All other similar items found require that the hub be rotated to the left, right, or down.  Down isn't a choice unless one's router is on the edge of a table.  Left and right are good as the adapter provides enough clearance for the hub so it doesn't contact the power cord or the Ethernet cable on the WAN port.

*File Systems & Summary of Boot Process: https://openwrt.org/docs/techref/filesystems

*opkg update

Please note, all of the above packages are not necessary.  But they do represent a broad range of tools that are very useful.  And since they don't take up a lot of space, it's worth installing them.  They don't run as active services or anything either, so no extra RAM or CPU usage unless one types the command.  Reboot after installing all of the above software.

Change a Volume Label;

====Performance Tuning for ExtX====

*tune2fs -o journal_data_writeback /dev/sdaX

====Performance Tuning for NTFS====

*If compression is also desired, add this in the above noted location: big_writes,compression

It is recommended to make sure the destination partition is the same size or larger of course.  Be prepared to wait a while, even on a USB 3.0 port.  

===Use an External Drive (USB Flash Drive, USB to mSATA) instead of internal Flash Memory using Overlay===

====Viewing Available Internal Partitions and Information====

See https://openwrt.org/toh/linksys/linksys_wrt1900ac, https://openwrt.org/toh/linksys/linksys_wrt1900acs, and https://openwrt.org/toh/linksys/linksys_wrt3200acm for Flash Memory Layouts of each AC Router Model.  The Flash Memory (non-volatile RAM / NVRAM) Layout is directly comparable to Partitions on a Personal Computer's disk drive or SSD.

Various commands to "see" the available internal Flash Memory partitions;

*UBI (Unsorted Block Images) Commands;

**ubinfo - provides information about UBI devices and volumes found in the system

Remember, the flash memory layout of the AC Series was created by Linksys, not Marvell.  And as noted by some, it seems a bit wasteful in how it was utilized.  

====Mounting Internal Partitions====

To view information about available UBI devices and partitions;

See http://www.linux-mtd.infradead.org/doc/ubi.html for additional information about UBI

=====Additional Notes=====

A side effect of the above behavior is it overwrites MWAN3 settings that are stored in /tmp/resolv.conf.auto.  If one has custom external DNS servers enabled for multiple WAN ports they will no longer be used.  This is not a flaw with OpenWRT, just a behavior to be aware of.  If one needs to configure specific upstream DNS servers, any custom DNS servers configured with MWAN can be configured within DNSMASQ.  Again, this is just something to be aware of.

Oddly, when doing a Google, Bing, etc search for these three terms: "resolvfile" "openwrt" "isc_dhcpd" NOTHING exists on the internet.  Until now that is.

When installing, be sure to disable or uninstall DNSMASQ.  Make sure DHCPD is installed if removing DNSMASQ (see DHCPD section below)

*opkg remove dnsmasq

opkg update

Enable and start the service (all of this is done automatically when the above packages are installed;

====Configuration====

If using Slave Zones, make sure permissions are set correctly for the Directory;

*chgrp bind /etc/bind/slaves

*To disable IPv6, add the following to the command line: -4

====Additional Information====

Make sure the BIND / NAMED configuration file includes 127.0.0.1 IP Address in both the allow-recursion and listen-on-port sections.  This can cause issues with DHCPD if it is not configured correctly.  See the MWAN3 and DHCPD sections for additional information.

===DHCPD (AKA isc-dhcp-server-ipv4, etc.)===

====Prerequisites & Things to Keep in Mind====

====Configuration & Management====

Default Configuration File (remember, this is a temporary file, so settings will not persist across router reboots): /tmp/run/dhcpd.conf

The Default Configuration File can be over-ridden by placing the DHCPD configuration file here: /etc/dhcpd.conf

DHCPD Executable / Binary File: /usr/sbin/dhcpd

But also keep in mind the settings changes in the /etc/init.d/dhcpd startup script only affect the DHCPD service.  The /etc/resolv.conf File still derives its settings from the /etc/config/dhcp File when the DHCPD service is restarted or the router is rebooted (same for DNSMASQ).  IE, the /etc/config/dhcp File should not be completely dismissed as useless.

====Special Note====

*If a custom /etc/dhcpd.conf file is NOT being used and the standard OpenWRT method of using /etc/config/dhcp method is used (again, HINT: Use a custom /etc/dhcpd.conf file), the DHCPD startup script erases the symbolic link that connects /tmp/resolv.conf --> /tmp/resolv.conf.auto in favor of its own custom /tmp/resolv.conf file (/etc/resolv.conf).  This can break DNS settings for networking in general and MWAN3.

stop_service()

{

rm /var/run/dhcpd.pid

}

</syntaxhighlight>The ''ln'' command corrects the symbolic link issue mentioned above.  And the ''rm'' command corrects the PID file issue that never goes away, again mentioned above.  Also note that if the DHCPD package is ever updated, the script will need to be modified again.  A startup script could be written, but haven't had time to write that yet.  This post gives a fairly goot hint on how to write it: https://askubuntu.com/questions/77149/how-to-find-text-and-replace-that-line-if-exists-with-terminal-otherwise-just-ap  Although regular expressions wouldn't be necessary, just a check to see if "stop_service" exists anywhere in the dhcpd startup script and if it doesn't, insert it at the end.

</IfModule>

DocumentRoot "/usr/share/apache2/htdocs"

find /usr/share/apache2 -type f -exec chmod 644 {} \;

</syntaxhighlight>

In other installations, such as Redhat or CentOS, apache or apache2 is referred to as HTTPD in binary / executables, configuration files, commands, etc.

*LoadModule proxy_scgi_module lib/apache2/mod_proxy_scgi.so (Module does NOT exist for OpenWRT)

*LoadModule cgid_module lib/apache2/mod_cgid.so (does NOT seem to work, even when setting the ScriptSock Directive)

====Lighttpd====

opkg update

=====PHP Configuration in /etc/php.ini=====

As noted previously, but worth mentioning again, OpenWRT names the interactive command line interface for PHP ''php-cli''.  Most sites give examples that use the command ''php'', so to make it easier create a symbolic link with this command: ln -s /usr/bin/php-cli /usr/bin/php  

=====Installing=====

**Move the database to an external eSATA drive: datadir        = /mnt/sdb3/mysql

**Move the tmp directory to an external eSATA drive: datadir        = /tmp (This directory is relative to the datadir, in that it will be created at the same level as the mysql directory, so this is not an abolute path where it will utilize the /tmp directory in the root of the file system)

*To create a password for the current user (blank if not configured): /usr/bin/mysqladmin -u root password 'new-password'

*Log into the command line for the database: mysql -u root -p or use phpMyAdmin see below

Show available storage engines: SHOW ENGINES\G or show engines;

*opkg update

*opkg install php7-mod-mbstring php7-mod-json php7-mod-hash php7-mod-ctype php7-mod-zip php7-mod-gd php7-mod-mysqli php7-mod-session php7-mod-snmp zoneinfo-northamerica (if one is in North America, if not, choose another zone and remember, phpMyAdmin will display a blank page with no error if a zoneinfo-WhatEverZone is not installed in addition to the zoneinfo-core package, see additional information below, dependencies will also be installed automatically).

*'''ALSO MAKE SURE TO INSTALL THE APPROPRIATE TIME ZONE MODULE, IN ADDITION TO THE DEFAULT''' zoneinfo-core: opkg install zoneinfo-northamerica (for example)

*wget <nowiki>https://files.phpmyadmin.net/phpMyAdmin/4.9.5/phpMyAdmin-4.9.5-english.tar.gz</nowiki> (or whatever the latest version is)

*tar -xzvf phpMyAdmin-4.9.5-english.tar.gz

*mv WhatEverUnTarredDirectory /usr/share/apache/htdocs OR WhatEverLighttpd Directory

**post_max_size = 128M

**max_file_uploads = 20

*To diagnose any issues when attempting to access the phpMyAdmin setup this will display the error message (look for the line that says WarnMissingExtension to spot missing modules): php-cli /usr/share/apache2/htdocs/phpMyAdmin/setup/index.php

=====LetsEncrypt / ACME=====

*opkg install htop restic luci-app-uhttpd libustream-mbedtls20150806 zoneinfo-northamerica

====Alternate Shells====

*https://www.howtogeek.com/68563/htg-explains-what-are-the-differences-between-linux-shells/

To install the ''chsh'' utility: opkg install shadow-chsh

===Samba Server and File Sharing===

*opkg install samba36-server OR opkg install samba4-server samba4-utils

*opkg luci-app-samba OR opkg install luci-app-samba4

*smbpasswd -a root (or whatever user is desired)

         # Below is the key to getting Samba Server to work with Windows 10

         map to guest = Never

Then dd a Network Share: In LUCI GUI, Service, Network Shares, General Settings or Edit Template Tab, enter a Name and a Path, the other defaults are fine.

And lastly, remember if one attempts to share the "Root Directory" ( / ), none of the sub directories will open, because of the way the OpenWRT file system works.

====Configuring PPTPD====

First, configure the /etc/config/pptpd file.  Below is a working example;<syntaxhighlight lang="text">

config service 'pptpd'

option 'enabled' '1'

option 'logwtmp' '0'

option 'username' 'AnotherUserNameETC'

option 'password' 'AnotherPaswordETC'

From there everything gets better.  The following files can be manually configured and the PPTPD startup script copies them to the /var/etc directory for the service to use when it starts up;

*/etc/pptpd.conf (see below for a working version of this file, slightly different than the default OpenWRT version)

*/etc/ppp/options.pptpd (see below for a working version of this file, slightly different than the default OpenWRT version)

Below is a working example of the /etc/pptpd.conf file;<syntaxhighlight lang="text">

option src 'wan'

option proto '47'

And one last thing to configure are couple of things the startup / shutdown script does not do.

====Additional Information====

*opkg update