DHCP Static Route broken by forbidden characters [Solved]

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bootit
DD-WRT Novice


Joined: 15 Oct 2024
Posts: 20

PostPosted: Fri Oct 18, 2024 17:41    Post subject: DHCP Static Route broken by forbidden characters [Solved] Reply with quote
Router Model
Asus RT-AC5300
Firmware Version
DD-WRT v3.0-r58568 std (10/15/24)
Kernel Version
Linux 4.4.302-rt232-st56 #12481 SMP Tue Oct 15 05:05:13 +07 2024 armv7l

Reference https://www.youtube.com/watch?v=eRhkv-hD8ZY

Using router defaults:

Setup>Network Setup
changed router default from 192.168.1.2

Maximum DHCP Users 253

Lease expiry 120 min

Status>LAN>DHCP Clients
Took two hosts and used the >Static Lease + button to add

Applied settings

RESULT:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82583V Gigabit Network Connection

DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::f1ae:f9e5:9021:27fa%8(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.201(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Saturday, 19 October 2024 3:10:36 AM
Lease Expires . . . . . . . . . . : Saturday, 19 October 2024 5:10:35 AM
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1

DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Ethernet 2:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82579V Gigabit Network Connection

DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::ca59:f0ee:8dc1:6fcf%9(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.64(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Saturday, 19 October 2024 3:10:36 AM
Lease Expires . . . . . . . . . . : Saturday, 19 October 2024 5:10:35 AM
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1

DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip. . . . . . . . : Enabled


AFTER CHANGES:

Ethernet adapter Ethernet:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82583V Gigabit Network Connection

DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::f1ae:f9e5:9021:27fa%8(Preferred)
Autoconfiguration IPv4 Address. . : 169.254.24.155(Tentative)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Ethernet 2:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82579V Gigabit Network Connection

DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::ca59:f0ee:8dc1:6fcf%9(Preferred)
Autoconfiguration IPv4 Address. . : 169.254.69.116(Tentative)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :


DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Enabled

Result
No function until set static IP in Windows 10 from DHCP
NB Same in DD-WRT v3.0-r58531

Look forward to your help!


Last edited by bootit on Wed Oct 23, 2024 8:01; edited 1 time in total
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bootit
DD-WRT Novice


Joined: 15 Oct 2024
Posts: 20

PostPosted: Sat Oct 19, 2024 2:24    Post subject: DHCP Static Route - Hostname only has alphanumeric and dash Reply with quote
I posted about the static route not working even after applying and rebooting the AC5300 and the PC using DHCP.

After 20 hours I checked and the static routes began working. Is DD-WRT designed to require some sort of time to pass to get DHCP static routes working?

[EDIT and SOLVED] I was wrong in this post because I was using forbidden characters in the
services/services/Static management/static leases/Hostname

As I was playing around with the fields I occasionally removed a forbidden character and it started working next time I check 20 hours later. This was lucky and unintentional. I edited all my entries copied from Merlin and ASUS firmware configurations (which allow forbidden characters) and fixed them by only using alphanumeric and dashes. DHCP now works!

I think this needs to be built into the router as a comment and added to the wiki for DHCP. Newcomers like me will not know this.

I refer to article on forbidden characters
https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=327370&sid=d63684a1c3e638b190f9f78e95cbca9a

DNSMasq will not start if it has forbidden characters in static leases or wrong settings in additional DNSMasq options
or other wrong settings so check that also

I've also had this problem. I've been through my static leases and removed all '_' and '#' and replaced by '-'
and DHCP server is now 'Enabled - Running'.
But - can anyone definitively say what the 'forbidden characters'are exactly? It's very well to say 'no forbidden characters'
but how do we know what is allowed and what is forbidden? Thanks. Smile

It is underscores in hostnames which prevent DNSMasq from starting. Hyphens are ok.
Been there, seen that ...

Forbidden characters in DNS include any character that is not a letter (a-z, A-Z), digit (0-9), or hyphen (-)


Last edited by bootit on Wed Oct 23, 2024 8:03; edited 4 times in total
eibgrad
DD-WRT Guru


Joined: 18 Sep 2010
Posts: 9354

PostPosted: Sat Oct 19, 2024 4:13    Post subject: Reply with quote
It's not clear from your description if you renewed the DHCP lease on your Windows machine (or rebooted it) after the change to the router. The fact it took nearly a full day strongly suggests it never did, and thus never knew of the static routes.

In general, updates to the router wrt DHCP and leases can be tricky because either the client or DHCP server may assume the current lease is valid. You sometimes have to literally delete the lease on the DHCP server *and* reboot the client to get things to change.

_________________
ddwrt-bind-static-routes-to-wan.sh (UPDATED! 11/12/24) * ddwrt-blacklist-domains.sh * ddwrt-dns-monitor.sh * ddwrt-ovpn-client-backup.sh * ddwrt-ovpn-client-killswitch.sh * ddwrt-ovpn-client-watchdog.sh * ddwrt-ovpn-server-watchdog.sh * ddwrt-ovpn-split-advanced.sh * ddwrt-ovpn-split-basic.sh * ddwrt-mount-usb-drives.sh * ddwrt-wol-port-forward.sh
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