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English Forums => 24.7, 24.10 Legacy Series => Topic started by: TomT on January 18, 2025, 11:57:04 PM

Title: Unknown interface, what is it ?
Post by: TomT on January 18, 2025, 11:57:04 PM
Hi
Today I've spent some time doing some housekeeping and general tidying up on my firewall.

I've noticed an interface called OPT5, but I don't know what this is.
It seems to be using the same interface as my WAN.

Can anyone advise what this is, and if it is needed or can it be removed?

Thanks
Title: Re: Unknown interface, what is it ?
Post by: Patrick M. Hausen on January 19, 2025, 12:10:38 AM
Your WAN seems to be a PPPoE link on top of igb0. Is this connected to a "DSL modem" or a similar device?

For your Internet connection there is no need to explicitly assign an interface to the igb0 port. But frequently people like to place an IP address on that interface to be able to connect to the modem's UI.

So possibly that is what you configured or tried to configure?

Why don't you just navigate to Interfaces > OPT5 to have a look what's up there? ;-)

Kind regards,
Patrick
Title: Re: Unknown interface, what is it ?
Post by: TomT on January 19, 2025, 12:18:11 AM
Good evening again Patrick.
I have an FTTP circuit which uses a PPPOE connection via a BT modem.

Looking at the interface there is nothing there and it's not enabled.

Enable:
Lock:
Identifier: opt5
Device:    igb0
Description: OPT5

I'm pretty certain it wasn't set up originally.
How should I have this setup ?

Thanks
Title: Re: Unknown interface, what is it ?
Post by: Patrick M. Hausen on January 19, 2025, 12:33:17 AM
If it's not enabled, you can most probably remove the assignment in Interfaces > Assignments and get rid of it.

Make a config backup, first! ;-)
Title: Re: Unknown interface, what is it ?
Post by: TomT on January 19, 2025, 01:00:48 AM
I'll give this a try in the morning.
Thanks
Title: Re: Unknown interface, what is it ?
Post by: dseven on January 19, 2025, 10:31:43 AM
Quote from: Patrick M. Hausen on January 19, 2025, 12:10:38 AMFor your Internet connection there is no need to explicitly assign an interface to the igb0 port. But frequently people like to place an IP address on that interface to be able to connect to the modem's UI.

There's *usually* no need, but another case for doing it would be to enable "baby jumbo frames", where ethernet frames up to 1508 bytes can accommodate full 1500 byte frames inside PPPoE. This requires altering the MTU on the underlying ethernet interface as well as the PPPoE one. The OpenReach network (that BT service is delivered over) does support this, but I'm not sure if BT (as the ISP) do or not.
Title: Re: Unknown interface, what is it ?
Post by: DEC670airp414user on January 19, 2025, 11:42:13 AM
interfaces > overview may give a better viewpoint?
Title: Re: Unknown interface, what is it ?
Post by: TomT on January 19, 2025, 12:21:04 PM
Morning.
I've removed it and so far nothing appears to be wrong :)
Hopefully it won't cause any issues.

Thanks