Month: April 2018

How to lookup your OSPF Router-ID

2018-04-21

By default ospf display Router-ID like IP address.

It’s possible to change this behavior and replace by a name.

Before:

R1#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
10.0.31.31 0 FULL/ - 00:00:39 10.0.99.2 Ethernet0/1
10.0.130.130 0 FULL/ - 00:00:36 10.0.10.2 Ethernet0/2

After:

ip host R3 10.0.130.130
ip host R2 10.0.31.31


ip ospf name-lookup

R1#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
R2 0 FULL/ - 00:00:38 10.0.99.2 Ethernet0/1
R3 0 FULL/ - 00:00:36 10.0.10.2 Ethernet0/2

Of course, fix the router-id.

How to configure PPPoE with CHAP

2018-04-21

Client:

interface Ethernet0/0
 no ip address
 ip virtual-reassembly in
 pppoe enable
 pppoe-client dial-pool-number 1
end

!
interface Dialer1
 ip address negotiated
 ip mtu 1492
 ip nat outside
 ip virtual-reassembly in
 encapsulation ppp
 dialer pool 1
 ppp chap hostname User1
 ppp chap password 0 Password1
 ppp ipcp route default     << To install default route
end

Server:

username User1 password 0 Password1
!
!
bba-group pppoe Group10
 virtual-template 10


interface Virtual-Template10
 ip unnumbered Loopback0
 ip mtu 1492
 peer default ip address pool Pool10
 ppp authentication chap

interface Ethernet0/2
 ip address 10.0.0.1 255.255.255.252
 pppoe enable group Group10


ip local pool Pool10 10.0.0.2

Verification:

client#sh ip int brief
Interface IP-Address OK? Method Status Protocol
Ethernet0/0 unassigned YES manual up up
<..>
Ethernet1/3 unassigned YES TFTP administratively down down
Dialer1 10.0.0.2 YES IPCP up up
NVI0 unassigned NO unset up up
Virtual-Access1 unassigned YES unset up up
server# sh ppp all
Interface/ID OPEN+ Nego* Fail- Stage Peer Address Peer Name
------------ --------------------- -------- --------------- --------------------
Vi2.1 LCP+ CHAP+ IPCP+ LocalT 10.0.0.2 User1


server# sh subscriber session brief
Current Subscriber Information: Total sessions 1

Uniq ID Interface State Up-time Identifier
6 Vi2.1 authen 00:12:49 User1

How to resolve ssh issue on Cisco ASA

2018-04-04

Tested in version 9.6(1)

~# ssh admin@x.x.x.x
Unable to negotiate with x.x.x.x port 22: no matching key exchange method fouer: diffie-hellman-group1-sha1

First method:

 # ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 admin@x.x.x.x
admin@x.x.x.x's password:
Type help or '?' for a list of available commands.
ASA1/act/pri>

Second method:

ASA1/act/pri(config)# ssh key-exchange group ?

configure mode commands/options:
 dh-group1-sha1 Diffie-Hellman group 2
 dh-group14-sha1 Diffie-Hellman group 14

ASA1/act/pri(config)# ssh key-exchange group dh-group14

ASA1/act/pri(config)# wr

Disconnect and reconnect:

# ssh admin@x.x.x.x
admin@x.x.x.x's password:
Type help or '?' for a list of available commands.
ASA1/act/pri> en