How to Add a Manual Persistent ARP Entry

1

I have been looking in IPFire Community Forum here, and I don’t see any topics.

I have a need to add an ARP entry in IPFire, so my Red0 can see the gateway of my ISP. Honestly, I don’t think that should need to be done, but after running into the same booting issue of Modem and Firewall, I am finding that I should probably do that.

Can anyone point me to some documentation of how to do that in IPFire? It doesn’t seem to be in the WUI.

I need something that can do the equivalent of something like this.

arp -i red0 -s ‘Internet IP’ ‘MAC’

2

I just manually run the command from IPFire SSH.

The entry it added is:

gateway ether ‘MAC Address’ CM red0

As far as I can make out for the flags,
C means a syntactically correct and complete entry
M means a permanent manual entry (It Doesn’t say Persistent, so I am wondering about that!)

Can anyone confirm or deny if what I am seeing about M is true or false? I just want a Persistent Sticky ARP entry that won’t go away on reboot.

Eric

3

Hi,

You can add a mac address under the option Networks.

Assign MAC Address

Joe.

4

Normal arp is only a cache that entries times out after some minutes so permanent means that the entry will not removed.

This cache never survive a reboot.

I hope it is early enough to add this to the start section of /etc/sysconfig/firewall.local
If this is to late you have to use an other initskript that run earlier.

5

From Command Line Interface, run setup > Networking > Gateway settings?

6

Thanks Arne for the thoughts

7

Ya know, I guess that was too simple, so I looked right over the obvious LOL. Thanks for lining me out!

8

That won’t work I don’t think. I have a Dynamic DHCP address. According to setup, it would only be used if Red is static.

image

9

I understand that portion but a mac table and an arp table isn’t exactly the same.

10

The mac addresses asssociated are with the red device. ie www.ipfire.org - Assign MAC Address
Thats what your cable modem or isp will see on the internet device and assign an ip address to. So if your ISP hard codes the device router etc downstream you might need to set the mac address. The ARP table is a table that shows other devices mac addresses so it can communicate with them. NIC’s dont work on ip, but the mac address. Sorry if I am teaching to suck eggs. You can associate a MAC address with an ip address using command line. However as Arne suggests it will go away after reboot. So you would need to add it to rc.local or somewhere to reset after a reboot. Not sure why you would want to assign a static MAC address to an IP. Not sure its a good idea though. As if the receiver changes mac you wont be able to communicate with it at all from the host holding the mapping.

HTH
JOe.