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本帖最后由 jresins 于 2025-2-27 22:55 编辑
组网：光猫桥接，RB5009拨号
背景：家里移动宽带年后突然拿不到IPv6地址，开始以为是封了我的v6地址，用 运营商送的路由器 和电脑拨号分别测了下，都能顺利拿到IPv6地址（也找过装维查询核实过，确实不是封禁导致的）。运营商送的路由器能拿到IPv6地址的前提是将WAN IPv6模式 改为PPPoEv6模式，默认的DHCP模式还是拿不到地址。
后面打算抓个报对比下 routeros的拨号流程和运营商送的路由器的拨号流程有啥区别。
不知有没有朋友遇到我一样的问题？是不是RouterOS v7不支持PPPoEv6导致的？
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以下补充抓包数据，供大家参考：
事实证明，BRAS是下发了/60的PD前缀的，但RB5009似乎无法感知到，导致一直无法拿到地址前缀，并循环发起Solicit请求
BRAS发出Router Advertisement
Frame 79: 126 bytes on wire (1008 bits), 126 bytes captured (1008 bits)
Ethernet II, Src: HuaweiTechno_3d:3f:13 (98:3f:60:3d:3f:13), Dst: Routerboardc_44:0c:25 (dc:2c:6e:44:0c:25)
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 6, Src: fe80::a66d:a4ff:feaf:a26d, Dst: ff02::1
Internet Control Message Protocol v6
Type: Router Advertisement (134)
Code: 0
Checksum: 0xb8d1 [correct]
[Checksum Status: Good]
Cur hop limit: 0
Flags: 0x40, Other configuration, Prf (Default Router Preference): Medium
Router lifetime (s): 1800
Reachable time (ms): 0
Retrans timer (ms): 0
ICMPv6 Option (Source link-layer address : a4:6d:a4:af:a2:6d)
ICMPv6 Option (MTU : 1492)
ICMPv6 Option (Prefix information : 2409:8a20:803:4683::/64)
RB5009请求PD前缀
Frame 80: 114 bytes on wire (912 bits), 114 bytes captured (912 bits)
Ethernet II, Src: Routerboardc_44:0c:25 (dc:2c:6e:44:0c:25), Dst: HuaweiTechno_3d:3f:13 (98:3f:60:3d:3f:13)
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 6, Src: fe80::927f:84e8:0:c, Dst: ff02::1:2
User Datagram Protocol, Src Port: 546, Dst Port: 547
DHCPv6
Message type: Solicit (1)
Transaction ID: 0x60a57f
Client Identifier
Option: Client Identifier (1)
Length: 10
DUID: 00030001dc2c6e440c20
DUID Type: link-layer address (3)
Hardware type: Ethernet (1)
Link-layer address: dc:2c:6e:44:0c:20
Link-layer address (Ethernet): Routerboardc_44:0c:20 (dc:2c:6e:44:0c:20)
Elapsed time
Option: Elapsed time (8)
Length: 2
Elapsed time: 0ms
Rapid Commit
Option: Rapid Commit (14)
Length: 0
Identity Association for Prefix Delegation
Option: Identity Association for Prefix Delegation (25)
Length: 12
IAID: 0000000c
T1: 0
T2: 0
BRAS Advertise PD前缀
Frame 81: 205 bytes on wire (1640 bits), 205 bytes captured (1640 bits)
Ethernet II, Src: HuaweiTechno_3d:3f:13 (98:3f:60:3d:3f:13), Dst: Routerboardc_44:0c:25 (dc:2c:6e:44:0c:25)
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 6, Src: 0:80fe::a66d:a4ff:feaf:a26d, Dst: fe80::927f:84e8:0:c
User Datagram Protocol, Src Port: 547, Dst Port: 546
DHCPv6
Message type: Advertise (2)
Transaction ID: 0x60a57f
Client Identifier
Option: Client Identifier (1)
Length: 10
DUID: 00030001dc2c6e440c20
DUID Type: link-layer address (3)
Hardware type: Ethernet (1)
Link-layer address: dc:2c:6e:44:0c:20
Link-layer address (Ethernet): Routerboardc_44:0c:20 (dc:2c:6e:44:0c:20)
Server Identifier
Option: Server Identifier (2)
Length: 14
DUID: 0001000663d3ebaa4846fbf59e32
DUID Type: link-layer address plus time (1)
Hardware type: IEEE 802 (6)
DUID Time: Jan 26, 2053 23:20:10.000000000 中国标准时间
Link-layer address: 48:46:fb:f5:9e:32
Link-layer address (Ethernet): HuaweiTechno_f5:9e:32 (48:46:fb:f5:9e:32)
Preference
Option: Preference (7)
Length: 1
Pref-value: 255
Identity Association for Prefix Delegation
Option: Identity Association for Prefix Delegation (25)
Length: 54
IAID: 0000000c
T1: 86400
T2: 138240
IA Prefix
Option: IA Prefix (26)
Length: 25
Preferred lifetime: 172800
Valid lifetime: 259200
Prefix length: 60
Prefix address: 2409:8a20:834:91c0::
Status code
Option: Status code (13)
Length: 9
Status Code: Success (0)
Status Message: Success
DNS recursive name server
Option: DNS recursive name server (23)
Length: 32
1 DNS server address: 2409:8020:2000::8
2 DNS server address: 2409:8020:2000::88
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2025年2月26日更新：找到原因了，BRAS下发的DHCPv6 Advertise 报文源地址错误，导致RouterOS IPv6防火墙将报文丢弃。注意下图中标红的源地址！BRAS正确的源地址应该是fe80::a66d:a4ff:feaf:a26d
下图是RouterOS IPv6防火墙的默认过滤策略，只有源地址在FE80::/10范围的DHCPv6报文会被允许进站
用移动送的路由器可以拿到IPv6地址 ，也说明了移动送的路由器对DHCPv6报文没有严格的过滤，存在一定隐患。 |
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310112100042806
发表于 2025-2-24 23:51
今天起来，发现RB5009直接不亮了，恢复也恢复不了，重启一分钟，所有网口直接没熄灯