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Hard code interface on a 4255

Can someone tell me if it is possible to hard code the interface settings on a 4255 to be 100 mbs full duplex.

I have attempted to modify the modules.conf file but it is not taking. Any help is appreciated, thanks

Cisco Employee

Re: Hard code interface on a 4255

With version 4.1 this is not supported.

With version 5.0 this is configurable under the "configure terminal -> service interface" configuration mode.


Re: Hard code interface on a 4255

Does this actually work in v5 though? It doesn't seem to be properly setting dupldex. After making these changes and rebooting the sensor, here is what I see:

88-nsmc-c1(config-int-phy)# show settings

name: Management0/0


media-type: tx


admin-state: disabled

duplex: full default: auto

speed: 100 default: auto


# cat /proc/net/cisco/

Description Intel(R) PRO/100 Network Connection

Driver_Name e100-cids

Driver_Version 2.3.40-cids, Mar 4 2005

PCI_Vendor 0x8086

PCI_Device_ID 0x1209

PCI_Subsystem_Vendor 0x8086

PCI_Subsystem_ID 0x0000

PCI_Revision_ID 0x0010

PCI_Bus 4

PCI_Slot 2

IRQ 16

System_Device_Name ma0_0

Current_HWaddr 00:0F:F7:75:56:CE

Permanent_HWaddr 00:0F:F7:75:56:CE

Part_Number 000000-000

Link N/A

Speed 100

Duplex half


Rx_Packets 10113

Tx_Packets 1858

Rx_Bytes 3684375

Tx_Bytes 262846

Rx_Errors 0

Tx_Errors 0

Rx_Dropped 0

Tx_Dropped 0

Multicast N/A

Collisions 8

Rx_Length_Errors 0

Rx_Over_Errors 0

Rx_CRC_Errors 0

Rx_Frame_Errors 0

Rx_FIFO_Errors 0

Rx_Missed_Errors 0

Tx_Aborted_Errors 0

Tx_Carrier_Errors 0

Tx_FIFO_Errors 0

Tx_Heartbeat_Errors 0

Tx_Window_Errors 0

Rx_TCP_Checksum_Good 0

Rx_TCP_Checksum_Bad 0

Tx_TCP_Checksum_Good 0

Tx_TCP_Checksum_Bad 0

Tx_Abort_Late_Coll 3

Tx_Deferred_Ok 10

Tx_Single_Coll_Ok 8

Tx_Multi_Coll_Ok 0

Rx_Long_Length_Errors 0

Rx_Align_Errors 0

Tx_Flow_Control_Pause 0

Rx_Flow_Control_Pause 0

Rx_Flow_Control_Unsup 0

Tx_TCO_Packets 0

Rx_TCO_Packets 0

Rx_Interrupt_Packets 10172

Perf 0, 0 i/p

TCB Ring Unused TCBs = 0 of 1024 total,cu=SUSPEND

RFD Ring Used RFDs = N/A

Netdev_Queue N/A

MPC Percent 0


Re: Hard code interface on a 4255

/etc/modules.conf is [apparently] rebuild on boot.

This is not supported, but here's what we do (v4.x):

make the modificatinos to /etc/modules.conf

mark /etc/modules.conf as immutable (man chattr)

# chattr +i /etc/modules.conf

now reboot and the interface should be whatever you set it to in /etc/modules.conf.


Re: Hard code interface on a 4255

Thanks for the info - very useful hint!

We did something similar, though less eloquent. We modified the script /etc/rc.d/rc3.d/S55.cid to prevent it from rewriting /etc/modules.conf every time the sensor was rebooted.

In effect, the same result from a different approach...

Either way though, I suspect Cisco will official declare that such a modification will in essence render the sensor unsupported, as this is an unapproved modification to the underlying OS via the service account, but I digress.

Again, thanks for sharing. I gave it "5 stars"... =)

Alex Arndt

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