HOWTO: Setup OpenWRT (LEDE) WiFi repeater (the right way)

openwrt_relayd_repeater.md

HOWTO: Setup OpenWRT (LEDE) WiFi repeater with IPv6 Support

1. Installation (Beginning of the guide)

Add after the relayd installation:

opkg install relayd odhcp6c
/etc/init.d/relayd enable
/etc/init.d/odhcp6c enable

What was added: odhcp6c package for DHCPv6 client support

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2. DHCP Configuration (/etc/config/dhcp)

Replace the entire DHCP section with:

config dhcp 'lan'
        option interface 'lan'
        option ignore '1'
        option dhcpv6 'relay'      # NEW: DHCPv6 relay
        option ra 'relay'          # NEW: Router Advertisement relay
        option ndp 'relay'         # NEW: NDP relay

config dhcp 'wan'
        option interface 'wan'
        option ignore '1'

# NEW: DHCPv6 relay configuration
config dhcp 'wwan'
        option interface 'wwan'
        option ignore '1'
        option dhcpv6 'relay'
        option ra 'relay'
        option ndp 'relay'
        option master '1'

What was added:

• Changed dhcpv6 'server' to dhcpv6 'relay'
• Changed ra 'server' to ra 'relay'
• Added option ndp 'relay' for Neighbor Discovery Protocol
• Added entire config dhcp 'wwan' section for wireless WAN relay

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3. Firewall Configuration (/etc/config/firewall)

Add at the end of the firewall configuration:

# NEW: IPv6 firewall rules
config rule
        option name 'Allow-DHCPv6'
        option src 'wan'
        option proto 'udp'
        option dest_port '546'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Input'
        option src 'wan'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        list icmp_type 'router-solicitation'
        list icmp_type 'neighbour-solicitation'
        list icmp_type 'router-advertisement'
        list icmp_type 'neighbour-advertisement'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

config rule
        option name 'Allow-ICMPv6-Forward'
        option src 'wan'
        option dest '*'
        option proto 'icmp'
        list icmp_type 'echo-request'
        list icmp_type 'echo-reply'
        list icmp_type 'destination-unreachable'
        list icmp_type 'packet-too-big'
        list icmp_type 'time-exceeded'
        list icmp_type 'bad-header'
        list icmp_type 'unknown-header-type'
        option limit '1000/sec'
        option family 'ipv6'
        option target 'ACCEPT'

What was added:

• DHCPv6 rule to allow DHCPv6 client communication
• ICMPv6 input rules for essential IPv6 protocols (ping, path MTU discovery, neighbor discovery)
• ICMPv6 forwarding rules for packet forwarding between networks

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4. Network Configuration (/etc/config/network)

Modify the lan interface and add new sections:

# Local network config
config interface 'lan'
        option force_link '1'
        option type 'bridge'
        option proto 'static'
        option ipaddr '192.168.2.1'
        option netmask '255.255.255.0'
        option gateway '192.168.1.1'
        option dns '192.168.1.1'
        option ip6assign '64'        # CHANGED: from '60' to '64' (standard)
        option _orig_ifname 'eth0 wlan0-1'
        option _orig_bridge 'true'
        option ifname 'eth0 eth1'

# WWAN (Wireless WAN) config
config interface 'wwan'
        option proto 'static'
        option ipaddr '192.168.1.2'
        option netmask '255.255.255.0'
        option gateway '192.168.1.1'
        option dns '192.168.1.1'

# NEW: IPv6 for WWAN
config interface 'wwan6'
        option ifname '@wwan'
        option proto 'dhcpv6'
        option reqaddress 'try'
        option reqprefix 'auto'

# STA Bridge (relayd) config
config interface 'stabrige'
        option proto 'relay'
        option network 'lan wwan'
        option ipaddr '192.168.1.2'

# NEW: Global IPv6 settings
config globals 'globals'
        option ula_prefix 'fd00::/48'

What was added:

• Changed ip6assign from '60' to '64' (standard IPv6 prefix length)
• Added entire config interface 'wwan6' section for DHCPv6 client on WWAN
• Added config globals 'globals' section with Unique Local Address prefix

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5. Verification Commands

## Verify IPv6 Configuration

After restarting services, verify IPv6 is working:

```bash
# Check IPv6 interfaces
ip -6 addr show

# Check IPv6 routing
ip -6 route show

# Test IPv6 connectivity
ping6 google.com
ping6 2001:4860:4860::8888

# Check DHCPv6 leases
cat /var/dhcp6.leases

Restart Services

/etc/init.d/network restart
/etc/init.d/firewall restart
/etc/init.d/odhcp6c restart
/etc/init.d/relayd restart
wifi reload

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Summary of Changes

1. Installation: Added odhcp6c package
2. DHCP: Changed from server to relay mode, added WWAN relay config
3. Firewall: Added 3 new rules for DHCPv6 and ICMPv6
4. Network: Added wwan6 interface, changed ip6assign to 64, added global IPv6 settings
5. Verification: Added new section with IPv6 testing commands

All changes maintain backward compatibility with IPv4 while adding full IPv6 support through relay mechanism.