Where do routers look for IOS configuration
datchcha
Member Posts: 265
in CCNA & CCENT
I am getting Contradicting answers from my study material. I thought the boot sequence for the IOS was the following
Flash, NVRAM, TFTP, ROM
But my sources are saying
NVRAM, Flash, TFTP, ROM
Why is that? I thought Flash stored the IOS – I am lost
Flash, NVRAM, TFTP, ROM
But my sources are saying
NVRAM, Flash, TFTP, ROM
Why is that? I thought Flash stored the IOS – I am lost
Arrakis
Comments
-
kafifi13
Member Posts: 259
Yes the Flash does store the IOS and NVRAM stores your startup config files.
-
georgemc
Member Posts: 429
datchcha wrote:kafifi13 wrote:Yes the Flash does store the IOS and NVRAM stores your startup config files.
So it is safe to say that a router will look in the following locations during boot for the IOS in this order?
Flash, NVRAM, TFTP, ROM
Are you asking about the configuration file or the IOS image. They're not the same thing. The NVRAM does not contain an IOS image.WGU BS: Business - Information Technology Management
Start Date: 01 October 2012
QFT1,PFIT in progress.
TRANSFERRED/COMPLETED: AGC1,BBC1,LAE1,QBT1,LUT1,QLC1,QMC1,QLT1,IWC1,INC1,INT1,BVC1,CLC1,MGC1, CWV1 BNC1, LIT1,LWC1,QAT1,WFV1,EST1,EGC1,EGT1,IWT1,MKC1,MKT1,RWT1,FNT1,FNC1, BDC1,TPV1 REQUIRED: -
datchcha
Member Posts: 265
georgemc wrote:datchcha wrote:kafifi13 wrote:Yes the Flash does store the IOS and NVRAM stores your startup config files.
So it is safe to say that a router will look in the following locations during boot for the IOS in this order?
Flash, NVRAM, TFTP, ROM
Are you asking about the configuration file or the IOS image. They're not the same thing. The NVRAM does not contain an IOS image.
I saw this one question that asked where the IOS configuration and the answer was
NVRAM, FLASH, TFTP, ROM
but i do not user stand that since NVRAM doesn't story to IOS image.
I even found this website http://www.svrops.com/svrops/documents/ciscoboot.htm
Notice the section labeled Located the IOS Software. It lists the same: NVRAM, FLASH, TFTP, ROm.Arrakis -
georgemc
Member Posts: 429
datchcha wrote:
I saw this one question that asked where the IOS configuration and the answer was
NVRAM, FLASH, TFTP, ROM
but i do not user stand that since NVRAM doesn't story to IOS image.
I even found this website http://www.svrops.com/svrops/documents/ciscoboot.htm
Notice the section labeled Located the IOS Software. It lists the same: NVRAM, FLASH, TFTP, ROm.
The IOS image can be in FLASH, TFTP, or ROM. When the router boots, it first looks for "boot system" commands (in the configuration file which in stored in NVRAM) pointing to an IOS Image in other than the default location (FLASH). It then then looks for an image in FLASH, then TFTP and as a last resort boots from the ROM.WGU BS: Business - Information Technology Management
Start Date: 01 October 2012
QFT1,PFIT in progress.
TRANSFERRED/COMPLETED: AGC1,BBC1,LAE1,QBT1,LUT1,QLC1,QMC1,QLT1,IWC1,INC1,INT1,BVC1,CLC1,MGC1, CWV1 BNC1, LIT1,LWC1,QAT1,WFV1,EST1,EGC1,EGT1,IWT1,MKC1,MKT1,RWT1,FNT1,FNC1, BDC1,TPV1 REQUIRED: -
datchcha
Member Posts: 265
georgemc wrote:datchcha wrote:
I saw this one question that asked where the IOS configuration and the answer was
NVRAM, FLASH, TFTP, ROM
but i do not user stand that since NVRAM doesn't story to IOS image.
I even found this website http://www.svrops.com/svrops/documents/ciscoboot.htm
Notice the section labeled Located the IOS Software. It lists the same: NVRAM, FLASH, TFTP, ROm.
The IOS image can be in FLASH, TFTP, or ROM. When the router boots, it first looks for "boot system" commands (in the configuration file which in stored in NVRAM) pointing to an IOS Image in other than the default location (FLASH). It then then looks for an image in FLASH, then TFTP and as a last resort boots from the ROM.
Thanks.Arrakis
