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ip route (default-gateway)

egeorgopoulos
Level 1
Level 1

I have a switch (R3) where doesn't contain any L3 routing, but only a VLAN interface. This connects to two upper switches (R1 & R2) which contain a static route (default gateway) the VLAN interface of R5. Switch R1 & R2 contain a HSRP IP.

I need to set up the default gateway, because there is something wrong with the routing that stands behind the R3.

My question is, if I enable the "ip routing" and set up the "ip route 0.0.0.0 0.0.0.0 IP of R1-R2 HSRP", will that contain a downtime? This switch (R3) has several servers that I don't want to affect their services.

I have attached a photo that describes the connectivity between the switches.

1 Accepted Solution

Accepted Solutions

Hello

Your Switch 3 should be a "host" switch (Layer2)  and should have only a managment ip address & default-gateway specified of the Layer 3 switch or router it attached to.

Also make sure ip routing is DISBALED on this switch and it has the correct L2 vlans in its database

res

Paul

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Please rate and mark as an accepted solution if you have found any of the information provided useful.
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Kind Regards
Paul

View solution in original post

7 Replies 7

Reza Sharifi
Hall of Fame
Hall of Fame

If the switch is layer-2 only, you don't need to enable IP routing.  You can simply add a default gateway point to r1-r2.

config t

ip default-gateway xx.xx.xx.xx

If the swith currenly does not have this command, there is no downtime when you add this command.

If the switch currently has this command and you want to change it to  "ip route 0.0.0.0 0.0.0.0 IP of R1-R2 HSRP" then there will be a short outage for the management vlan.

HTH

What is your problem your are not able to ping switch or from switch you are not able to ping cleints.

If this is the case just input

ip default-gateway

Nothing will be effected in that case.

If u will enable IP routing all your traffice will be effected and it will require downtime.

Jawad

Jawad

my problem is that there is a server behind the switch R3 with default gateway that resides on a network that is above the switch R5 and cannot reach it. When this server is behind the switch R5, which has default-gateway, there is no problem.

So, that is why I thought that the default-gateway should be applied on the switch R3 as well.

Hello

Your Switch 3 should be a "host" switch (Layer2)  and should have only a managment ip address & default-gateway specified of the Layer 3 switch or router it attached to.

Also make sure ip routing is DISBALED on this switch and it has the correct L2 vlans in its database

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Indeed, this switch is only L2 with management ip aaddress, but with no default-gateway. My question is if I set up the "default-gateway" will I have any downtime?

Hello

No the default-gateway is only used for remote management purposes of the switch itself, adding it will not disrupt services.

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Hi,

You can follow any one of this, as mentioned by Paul they are non SI change & only affect Mgmt access for few sec

1) you can disable “IP routing” & static/default route , Only “IP default-gateway --> IP Address” will be present on the switch

OR

2) you can disable “IP default-gateway --> IP Address ” & enable “IP routing” & static/default route config.

Br/subhojit

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