3560 Route Table Information

[tohoken]

All,

I have a strange thing going on.  Well, strange to me anyways.  We have a 3560 switch that does not have IP routing enabled.  However, when I do a show IP route I get a table with a couple of entries.  There is the table I see:

IDF16-Switch01#sh ip route
Default gateway is 10.4.4.1

Host               Gateway           Last Use    Total Uses  Interface
10.15.1.2          10.4.0.2              0:02         13976  Vlan4
10.2.126.30        10.4.0.2              0:01        173741  Vlan4

However, these are not static routes or learned routes.  I cannot remove them at all.  I have tried everything.  My problem is that the gateway listed is no longer in use and the 10.15 host is my workstation so when I try to SSH into the switch I cannot due to the incorrect gateway.  If I try to SSH to the switch from any IP no on this list it works.  So, my question is Where could the switch be getting this info and how do I remove it?  Any help would be appreciated.

Thanks,

Ken

[Peter Paluch · Accepted solution]

Hi Ken,

These entries are most probably created thanks to the ICMP Redirect messaging, and I guess you would get the same output with the show ip redirects command. You should be able to clear these entries using the clear ip redirect command - give it a try and please let us know if it worked.

Best regards,

Peter

[tohoken]

Peter,

Thank you very much.  That worked like a charm.  Seems so simple now but I have never run into this before. 

Ken

[cadet alain]

Hi Peter,

I didn't think about this, what a shame! As always you're the best.

Regards.

Alain.

[Peter Paluch]

Hi Alain,

Hey, no problem. I see this particular issue often (my students often forget to use the ip default-gateway command on their switches so they end up being dependent on ProxyARP and ICMP Redirects to reach diverse networks from their L2 switches) so it was kind of familiar to me.

As always you're the best.

Thank you - but no way. There are far more experienced and knowledgeable experts around here.

Best regards,

Peter

[cadet alain]

Hi,

Default gateway is 10.4.4.1

It is getting this info from the ip default-gateway global command, to verify just do a sh run | i ip default-gateway.

Host               Gateway           Last Use    Total Uses  Interface
10.15.1.2          10.4.0.2              0:02         13976  Vlan4
10.2.126.30        10.4.0.2              0:01        173741  Vlan4

this gateway probably gave you the ip you see  due to  proxy-arp . I would clear arp cache: clear ip arp interface Vlan4 and then I would enable and disable ip routing: ip routing, no ip routing.

Let us know .

Regards.

Alain.