Can't telnet in from one VLAN

[spj2019]

Hi,

I'm using a 3650 with routing, IOS 15.3. Up to now we've only needed console access, but new requirements have led us to setup remote access. After setting up the vty configuration and user, we get a Connection Refused message when attempting to telnet in from a directly connected PC on the same network segment. We also defined the snmp server but when we tried accessing it we get no response. Ping works fine. If I telnet in from the console connection, we get a user name prompt. 

Since we have two VLANs defined (vlan1 and vlan799) , we redefined the switch port and set it to vlan1 (it was on vlan799 before), changed the IP address on the PC and bingo! both telnet and snmp were responding and working properly. Still can't get it to work on vlan799 though. Any ideas about what could be the problem? could it possibly be the high vlan number? sounds weird. 

Thanks for any advice!  

[Seb Rupik]

Hi there,

Do you have MPP configured on the switch:

https://www.cisco.com/c/en/us/td/docs/ios/security/configuration/guide/sec_mgmt_plane_prot.html

...what is the output of :

show management-interface

sh run | beg control-plane host

Also check for ACLs applied to the vty line config:

sh run | beg line vty

...and also the snmp-server statements:

sh run | inc snmp

...in both cases you may have an ACL which only permits traffic sourced from VLAN1 and not VLAN799 .

cheers,

Seb.

[paul driver]

Hello

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@spj2019 wrote:

Hi,

I'm using a 3650 with routing, IOS 15.3. Up to now we've only needed console access, but new requirements have led us to setup remote access. After setting up the vty configuration and user, we get a Connection Refused message when attempting to telnet in from a directly connected PC on the same network segment. We also defined the snmp server but when we tried accessing it we get no response. Ping works fine. If I telnet in from the console connection, we get a user name prompt. 

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Do you have any access list, management plane policing, or specifying any telnet/ssh source interface applied to the switch

Would you be able to post the configuration of your switch please?

[spj2019]

Hi, thanks for your reply. There are no Acls defined yet. I won't be at the site for a few days, so I only have a part of the config...