Guest WiFi + abuse control for beginners

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Wiki Path: DD-WRT Wiki Main / Tutorials / Guest_Network / Guest WiFi with Abuse Control


Contents

[edit] Introduction

This tutorial is for beginners, and therefore before proceeding make sure you have working reset button and have backed up you configuration (so you can reset your router and restore configuration if you stuck somewhere). This guide will show you the basics of creating and controlling Guest WiFi.

Creating Guest VAP
Creating Guest VAP
Adding DHCP for Guests
Adding DHCP for Guests
Hardcoded limiting interfaces
Hardcoded limiting interfaces
Setting priorities
Setting priorities
Abuse control
Abuse control
Web content filtering
Web content filtering
Content blocked
Content blocked

[edit] Instructions

For that purpose we will first create Virtual Access Point (VAP) for Guests.

On the Wireless->Basic Settings tab, click 'Add' in the 'Virtual Interfaces' section. Enable AP isolation so that guests can not see each others. AP Isolation drops all traffic between clients connected to the VAP. This is recommended if you want secure Guest WiFi to help mitigate wireless snooping attacks. Then go to the Wireless Security tab to set the security type and wireless network password.

Set Network Configuration to Unbridged, Enable NAT (so that guest can have internet), and enable Net isolation (this creates a couple firewall rules that block guests from the private network). Net isolation works ONLY on an unbridged interface on newer builds, starting from build:

  • Broadcom 23020, Atheros 24759, Mediatek (Ralink) 25934

AP Isolation = Guests can not see each other on guest VAP
Net isolation = Guests can not see your private LAN+WLAN

Enable Forced DNS Redirection and enter the OpenDNS server IP (208.67.222.222) in the Optional DNS target field. This will prevent users from using their own DNS servers (and hence get around content filtering) by intercepting DNS queries and forcing them to use the DNS servers you specify. Enter the IP Address and Subnet Mask (e.g. 172.16.1.1./255.255.255.0 ) Click Save then Apply then wait ~30sec for the new interface (e.g. ath0.1) to be created. Note: You still wont be able to connect to this Guest VAP. You must enable DHCP for the clients.

Next step is to enable DHCPd for the guest wifi. Go to Setup->Networking, in the DHCPd section add a dhcp server for the new guest network (Add then choose the VLAN (e.g. ath0.1) from drop down menu. Select starting and max number of IP addresss, plus lease time. Click Save then Apply. Wait about 30sec and try to connect to Guest WiFi. If not working, power cycle the router. You should be able to browse Internet but not reach your private network nor see other clients on network discovery.

  • For a newer method that uses dnsmasq instead of dhcpd, see Guest Network

[edit] Quality of Service (QoS)

This is for bandwidth limiting. Put the private network on Maximum and Guest to Bulk. The Bulk class is only allocated the remaining bandwidth when other classes are idle. If the pipe is full of traffic from other classes, Bulk will only be allocated 1% of total set limit. This is so your guests will not affect your private speed. Alternatively, you can manually set hard-coded limits.

With interface limiting both bridged & unbridged, offers ability to rate or priority limit services or port(s) ranges. This can be exceptionally useful to control bandwidth hogs, regulate hotspots, etc. with an interface limit, to prevent guest users trying circumvent QoS limits by changing IP and/or MAC addresses. Abusive users can't bypass your rules without switching off the interface.

Example:

   vlan1 512/512 0 ssl manual 

This means all traffic on vlan1 interface (lan ports for some routers, others use eth) is not limited nor shaped, & goes "up to" global limits, except ssl traffic, being limited to 512kbps both up & down (64KB/s). Multiple entries are also possible, for example:

   ath0 512/512 0 ssl manual 
   ath0 2048/512 0 http manual 
   ath0 512/512 0 ftp manual 

The same applies to what was said above, just for the ath0 wireless interface & only the listed services are rate limited. Priority limits can also be used, but simultaneous rate limiting & prioritizing on the same service is not supported.

[edit] Access Restrictions

Access Restrictions can be used to block torrents and some VPNs. A determined user is very hard to block because now there are free SSTP VPN services, etc. On cheap routers you can not run Proxy, Squid, etc, so this is all we have, so to do some net abuse filtering we will use OpenDNS.

[edit] What is OpenDNS?

OpenDNS is a free DNS (Domain Name Server) service to make internet browsing safer and allegedly faster. By simply using their DNS servers instead of the ISP, you are automatically protected from their list of Phishing websites. However, in order to restrict e.g. adult website content, you will need to create a free account, register your IP address, and select the categories you want restricted (i.e. sexuality, nudity, pornography, lingerie, grotesque, etc.). Since most of us have DHCP assigned WAN IP addresses that change periodically, we need to instruct our router to tell OpenDNS the new IP address when it changes: see DNS-O-MATIC. Reboot router, clear browser cache, and manually set public dns server in your PC NIC adapter to try to avoid restrictions.