Hello there!
I have Xiaomi R3G router with the latest OpenWRT firmware 19.07.3.
WiFi 5 GHz and wired connection is fine, DHCP works properly.
But clients WiFi 2.4 GHz cannot get IP address from server.
Trying to dump dhcp traffic:
tcpdump -i wlan0 -pn -vv port 67 and port 68
All I get is:
Summary
root@OpenWrt:~# tcpdump -i wlan0 -pn -vv port 67 and port 68
tcpdump: listening on wlan0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:57:24.678778 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:24.678765 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:29.682100 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 5, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:29.682195 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 5, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:33.403039 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 8, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:33.403138 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 8, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:41.898149 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 17, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:41.898313 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 17, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:58.727561 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 34, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:57:58.727667 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xa2373de0, secs 34, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:58:02.189973 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xe8d7eb51, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
11:58:02.189931 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 314)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 00:0a:f5:f0:c8:79, length 286, xid 0xe8d7eb51, Flags [none] (0x0000)
Client-Ethernet-Address 00:0a:f5:f0:c8:79
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether 00:0a:f5:f0:c8:79
MSZ Option 57, length 2: 1500
Vendor-Class Option 60, length 15: "android-dhcp-10"
Parameter-Request Option 55, length 10:
Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name
MTU, BR, Lease-Time, RN
RB, Vendor-Option
As I can see the requests is trying to get IP address but DHCP server on my router is not responding.
How to fix this issue?
Thx for reply!