Using expect with Cisco IOS

Following up my JunOS post, here is a handy script I cooked up to pull the configuration from a Cisco IOS device.  The one trip up for this stuff is sometimes you can logon to a cisco device, and you can be at the enabled state, you may have to enable,  and depending on how it’s configured you may have to use an enable password, which may be your password (again) or you may have to use a different password.

So yeah with a bunch of testing around this seems to work well enough for me.

#!/usr/local/bin/expect —
set MYUSER “my_user_name”
set MYPASS “my_password”
set ENPASS “my_enable_password”

set HOST [lindex $argv 0];
set timeout 90
if {$argc!=1} {
puts “Usage is scritpname <ip address>\r”
exit 1

puts “Connecting to $HOST\r”

spawn ssh $HOST -l $MYUSER

# Deal with hosts we’ve never talked to before
# or just logon
expect {
“*yes/no*” {send “yes\r” ; exp_continue }
“*assword:” {send “${MYPASS}\r” }
expect {
“\r*>” {}
“\r*#” { set ALREADY 1}
“*enied” {exit 1}
“*assword” {exit 1}

if { $ALREADY < 1 } {

send “enable\r”
expect “*assword:” {
send “${MYPASS}\r”
expect {
“*enied” {
send “enable\r”
expect “*assword:”
send “${ENPASS}\r”
expect {
“*enied” {
exit 1}
“\r*#” {}
“\r*#” {}

send “show run\r”

expect {
“ore” {send ” “; exp_continue}
“\r*#” {}

#Let’s get out of here
send “q\r”
expect eof
exit 0


This is a little more cleaner than the prior JunOS one, as I’ll keep on improving it.

It works with ASA’s (tested 8.2)and IOS (tested 12.2)

Configuring IPX/SPX

Much like my prior article on Configuring TCP/IP, the process for configuring IPX/SPX on a cisco router is pretty much the same thing.

The first big ‘gottcha’ in the world of IPX is that it supports multiple frame types.  This winds up leading to all kinds of troubles when various people setup various servers.  It is inevitable that people pick their own and incompatible frame type.  The only to ‘fix’ this is for everyone to be on the same type.  I have heard of people using different frame types for different environments, much like using 802.1q (trunking) to separate various peoples traffic who do not want to see each-others resources.  But back when IPX was prevalent, people were still using HUBS which mirror all traffic, and primitive layer two switching at best.  Not to mention with the advent of Netware 4, you could have virtual NIC’s in the server and workstations, and bind to all possible frame types.

Things got messy, and quick.

But I digress, for this example I’m going to use the ‘default’ frame type of ETHERNET_802.2 or SAP is cisco speak.  Mostly because I don’t feel like fully configuring the MS-DOS client I managed to dig up, and mostly because at this point (2013) I really don’t care what frame type I use.

I’m going to setup the following IPX networks:

WAN C0000001
SERVER C0010001
USER C0010002

The first step is to enable the ipx protocol on the router.  This is done with the ‘ipx routing’ command.

corertr1#config t
Enter configuration commands, one per line. End with CNTL/Z.
corertr1(config)#ipx routing

Now the IPX protocol is enabled.  The next step is to configure the ethernet interfaces.  This is pretty straightfoward, we put in the network numbers, and assign the correct frame types.

corertr1#config t
Enter configuration commands, one per line. End with CNTL/Z.
corertr1(config)#int eth1/0
corertr1(config-if)#ipx encapsulation SAP
corertr1(config-if)#ipx network c0010001
corertr1(config)#int eth1/1
corertr1(config-if)#ipx encapsulation SAP
corertr1(config-if)#ipx network c0010002
corertr1(config)#int fa0/0
corertr1(config-if)#ipx network c0000001
corertr1(config-if)#ipx encapsulation SAP

Now we can quickly check the interfaces that IPX is running on with the ‘show ipx interface brief’ command.  You should get something like this:

corertr1#show ipx interface brief
Interface IPX Network Encapsulation Status IPX State
FastEthernet0/0 C0000001 SAP up [up]
FastEthernet0/1 unassigned not config’d admin down n/a
Ethernet1/0 C0010001 SAP up [up]
Ethernet1/1 C0010002 SAP up [up]
Ethernet1/2 unassigned not config’d admin down n/a
Ethernet1/3 unassigned not config’d admin down n/a
Ethernet1/4 unassigned not config’d admin down n/a
Ethernet1/5 unassigned not config’d admin down n/a
Ethernet1/6 unassigned not config’d admin down n/a
Ethernet1/7 unassigned not config’d admin down n/a

So far, so good.  Now the next question is, does the router see the server?  And what kind of services are available on the network?  This can be found with the ‘sho ipx servers’ command.

corertr1#sho ipx servers
Codes: S – Static, P – Periodic, E – EIGRP, N – NLSP, H – Holddown, + = detail
U – Per-user static
3 Total IPX Servers

Table ordering is based on routing and server info

Type Name Net Address Port Route Hops Itf
P 4 FPNWDC_NW DEAD0001.0000.0000.0001:0451 2/01 1 Et1/0
P 444 VIRTUALLYFUN!FPNWDC DEAD0001.0000.0000.0001:84C8 2/01 1 Et1/0
P 640 FPNWDC DEAD0001.0000.0000.0001:E885 2/01 1 Et1/0

Everything is looking good!  As you can see my virtual Netware server (FPNW on NT 4.0) is type 4, and called FPNWDC_NW.  SAP types 444 and 640 are for Windows NT, with 444 being the NetBIOS Browser/Domain control service.

IPX is a rather chatty protocol, and it is easy for things to go wrong.  Another fun command is ‘show ipx traffic’ which will let you get some idea of what kind of chat is going on.

corertr1#show ipx traffic
System Traffic for 0.0000.0000.0001 System-Name: corertr1
Time since last clear: never
Rcvd: 149 total, 34 format errors, 0 checksum errors, 0 bad hop count,
100 packets pitched, 29 local destination, 0 multicast
Bcast: 126 received, 64 sent
Sent: 79 generated, 18 forwarded
0 encapsulation failed, 2 no route
SAP: 0 Total SAP requests, 0 Total SAP replies, 3 servers
0 SAP general requests received, 4 sent, 0 ignored, 0 replies
0 SAP Get Nearest Server requests, 0 replies
0 SAP Nearest Name requests, 0 replies
0 SAP General Name requests, 0 replies
18 SAP advertisements received, 15 sent, 0 Throttled
4 SAP flash updates sent, 0 SAP format errors
RIP: 2 RIP requests, 0 ignored, 2 RIP replies, 4 routes
9 RIP advertisements received, 30 sent 0 Throttled
7 RIP flash updates sent, 0 atlr sent
4 RIP general requests sent
0 RIP format errors
Echo: Rcvd 0 requests, 0 replies
Sent 10 requests, 0 replies
0 unknown: 0 no socket, 0 filtered, 0 no helper
0 SAPs throttled, freed NDB len 0
0 packets received, 0 replies spoofed
Queue lengths:
IPX input: 0, SAP 0, RIP 0, GNS 0
SAP throttling length: 0/(no limit), 0 nets pending lost route reply
Delayed process creation: 0
EIGRP: Total received 0, sent 0
Updates received 0, sent 0
Queries received 0, sent 0
Replies received 0, sent 0
SAPs received 0, sent 0
Trace: Rcvd 0 requests, 0 replies
Sent 0 requests, 0 replies

In this brief guide, I’m not going to even get into all of this, however it is important to know that the router has sent things, and received things back.

Another thing that is different about IPX vs TCP/IP is that each server has it’s own internal network, where the services originate from.  You can see this with the show ipx route command

corertr1#show ipx route
Codes: C – Connected primary network, c – Connected secondary network
S – Static, F – Floating static, L – Local (internal), W – IPXWAN
R – RIP, E – EIGRP, N – NLSP, X – External, A – Aggregate
s – seconds, u – uses, U – Per-user static/Unknown, H – Hold-down

4 Total IPX routes. Up to 1 parallel paths and 16 hops allowed.

No default route known.

C C0000001 (SAP), Fa0/0
C C0010001 (SAP), Et1/0
C C0010002 (SAP), Et1/1
R DEAD0001 [02/01] via C0010001.5254.0012.3456, 10s, Et1/0

As you can see from the SAP advertisements above, and the route here, the server is configured for it’s internal network to be DEAD0001.  The router picked up the advertisement from C0010001.5254.0012.3456, which breaks down as c0010001 being the network the server is on (the server network), and 5254.0012.3456 being the MAC address of the server.

The real test comes from trying to use a client.

Screen Shot 2013-10-22 at 1.26.35 PM

Netware 3.12 client

As you can see, this MS-DOS client attached to the client vlan, can see and interoperate with the virtual NetWare server.

This pretty much covers the basics of getting IPX/SPX working.  Logically the next thing to do would be to configure routing and get IPX working throughout the WAN.  But I’m going to save that for a later time.

The more ‘advanced’ topics of IPX involve filtering, as it was a common problem in large networks where you could simply have too many servers, and they would be constantly talking among themselves.  Another problem is licensing, where some products are licensed in certain areas, and you want those licenses to stay in a geographic area.  Latency was another issue too, it was insane to say use a SNA server in Japan, to talk to a mainframe in Arizona when you were in Arizona.  Or if you had a 3rd party, and you only wanted them to connect to a print server, and a single file server, you would setup access-lists on your peer router, much in the same way that we setup firewalls in this fine modern age 😉

Adding some substance to my example network

So thanks to I thought I should add some people and setup various workstations around my fake network. With that said, here is my list:

name user id country PC
Hazel B. Forrest hforrest USA MS-DOS
James M. White jwhite USA Windows 3.1
Russell I. Ward rward USA
Valerie H. Shimp vshimp USA
Vera H. Williams vwilliams USA
Marie J. Brown mbrown UK Windows 95
Jason S. Seymore jseymore UK
Mingmei Hao mhao HK OS/2 1.21
Guang Huang ghuang HK
Wit Pawlak wpawlak PL WindowsNT 4.0
Fabio Napolitani fnapolitani IT

Which is enough to get me started in creating some users.

For starters I thought it would be fun to make up some applications the users can ‘use’ on this fine network.  A mainframe is a must, however Hercules doesn’t emulate SNA networks.  Which is kind of sad.  I did find an evaluation copy of Microsoft SNA Server 2.11 which runs great on NT 3.5 and higher.  However it is limited to two sessions, but to be honest back when I used a mainframe for work, Microsoft SNA server was honestly the best thing out there.  I had a NT 4.0 / SNA 2.11 install that had uptime in YEARS, while the later SNA 3.0, 4.0 and HIS stuff constantly had issues.

For email, I thought I’d go with something positively ancient, Microsoft Mail 2.1c.

Microsoft Mail

Microsoft Mail

Back then, email programs were just flat databases that allowed multiple people to read/write/lock files over a network. It is very reminisce of how BBS multiuser doors & databases work. MS Mail 2.1 includes clients for MS-DOS, Windows 3.X while the later 3.5 version included an OS/2 client that used the WLO libraries, which was a port of Windows 3.0 to run on top of OS/2.  I kind of covered this thing back here, although it was mostly geared to version 3.5, it basically is the same thing.

I’ve been using a Windows NT 4.0 server loaded up with the FPNW, so it looks like a NetWare server.  Although Netware 3.12 runs on Qemu 0.90, it is lacking UDP bridge support to communicate with dynagen/dynamips.  I did find out that VirtualBOX does support the UDP bridge, and will even run Netware 3.12, HOWEVER, after transferring a few megabytes, the server will stop responding, and dynamips will crash.  Not a very satisfactory solution.  So until I get around to backporting the UDP code, this NT server will serve as my virtual ‘Netware’ server for the time being.

I was also going to run SQL Server 4.21a on WindowsNT, however I did come across SQL Server for OS/2, so I will be installing an OS/2 machine complete with Lan Manager, and SQL Server.  The only downside is that LanManager relies on the non-routable NetBEUI protocol.  However it is just as awkward as bridging mainframe traffic, so I guess that is a hidden plus. While a program to talk to the database outside of the old isql stuff would be nice, I suspect that doing anything beyond Visual Basic + ODBC would take too much time, and honestly not really be all that worth it.

Also looking at this fine program, Stomper, which lets your share a modem over a network, I thought it would be fun to try in combination with rlfossil for some BBSing adventures.  Back before the internet was open to commercial ISPs it wasn’t uncommon for corporations to pool modems over a LAN.  Remote access was typically handled with specialized hardware appliances like the Shiva LanRover. As far as I know, the only real dialup server that Microsoft had was incorporated with Windows NT 3.5.

Once I get this networking operating correctly, then I’ll start to add things like redundancy via HSRP in my core site, backup network connections, an internet connection, upgrade to an exchange server, some BGP peering, and a VPN server.

Just like the real world!

Configuring TCP/IP

Cisco routers are born to do TCP/IP.  And looking at the networking world today, it is pretty safe to say that you will be on a TCP/IP network.  Luckily configuring TCP/IP on the router is pretty easy.  IP addresses are assigned per interface, as a typical router will have many ip addresses.

As always it does help to have a ‘plan’ for what ip addresses will go where in your network.

I’m using the network that I described earlier, here.

From my corertr1 router I’m going to setup 3 networks, a server network, a user network, and finally a network to connect to my WAN router.  The IP networks that I’m going to use are the following:


The first thing I want to do is examine the existing configuration of the FastEthernet 0/0 port which will be my ‘wan’ network port.

corertr1#sho run int fa0/0
Building configuration…

Current configuration : 83 bytes
interface FastEthernet0/0
no ip address
duplex auto
speed auto

As you can see it is shut down, and has no ip address assigned.  We can also check the ethernet’s status with a show interface fa0/0

corertr1#sho interfaces fastEthernet 0/0
FastEthernet0/0 is administratively down, line protocol is down
Hardware is i82543 (Livengood), address is ca00.383b.0008 (bia ca00.383b.0008)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:02:30, output 00:01:40, output hang never
Last clearing of “show interface” counters 00:00:01
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

The important part here is this line:

FastEthernet0/0 is administratively down, line protocol is down

First the interface is ‘administratively down’ meaning that it is configured this way. In cisco speak this interface is ‘down, down’. This is different from a ‘up/down’ interface that is configured to be ‘up’ or operational, but is not working.  That will appear like this:

FastEthernet0/0 is administratively up, line protocol is down

Which indicates that there is a hardware problem.

The first thing we are going to do is turn the interface ‘on’.

corertr1#config t
Enter configuration commands, one per line. End with CNTL/Z.
corertr1(config)#interface fastEthernet 0/0
corertr1(config-if)#no shut
16:41:01: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up
16:41:01: %SYS-5-CONFIG_I: Configured from console by console
16:41:02: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

Notice that when we type in “interface fastEthernet 0/0” the prompt changes to (config-if) meaning that we are now configuring an interface.  Type in the question mark, and you can see all the possible options you have on this interface.  The physical interface is where you select things like speed, duplex, line encapsulation.  If the interface doesn’t have any ‘virtual’ members like 802.1Q, or frame relay as a few examples, you can put an ip address on the interface.  Also take note that when I typed in the first ‘exit’ the prompt changed back to (config) meaning we are no longer configuring the fastEthernet 0/0 interface.  The next exit then takes us out of the config mode all together.

The next thing that happens is that the router turns the interface on, and then generates a syslog event which is followed by a console message letting us know that that fastEthernet interface is now operational as its state is now up.

Now I’m going to go back into the configuration mode, and setup the IP address

corertr1#config t
Enter configuration commands, one per line. End with CNTL/Z.
corertr1(config)#interface fastEthernet 0/0
corertr1(config-if)# description WAN network
corertr1(config-if)# ip address

Notice that I also set a description on the interface.  This makes it easier to remember what goes where.  Always if possible put in descriptions! Now if we check the interface configuration we will now see:

corertr1#sho run interface fastEthernet 0/0
Building configuration…

Current configuration : 119 bytes
interface FastEthernet0/0
description WAN network
ip address
duplex auto
speed auto

Which looks fine.

Another GREAT feature of the cisco routers is the CDP protocol, or cisco discovery protocol.  CDP will broadcast on every interface a special packet that other cisco devices will pick up on, to let you know that who/what you are plugged into.  To take a look simply run the command show cdp neigh

corertr1#sho cdp neigh
Capability Codes: R – Router, T – Trans Bridge, B – Source Route Bridge
S – Switch, H – Host, I – IGMP, r – Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID
corewan1 Fas 0/0 134 R 7206VXR Fas 0/0

This tells us that our Fast ethernet 0/0 is connected to a 7206VXR called corewan1 on it’s Fast ethernet 0/0.  You can get even more information with the command ‘show cdp neighbors detail’

corertr1#show cdp neighbors detail
Device ID: corewan1
Entry address(es):
Platform: cisco 7206VXR, Capabilities: Router
Interface: FastEthernet0/0, Port ID (outgoing port): FastEthernet0/0
Holdtime : 129 sec

Version :
Cisco Internetwork Operating System Software
IOS ™ 7200 Software (C7200-JS-M), Version 12.2(31), RELEASE SOFTWARE (fc2)
Technical Support:
Copyright (c) 1986-2005 by cisco Systems, Inc.
Compiled Thu 11-Aug-05 15:57 by tinhuang

advertisement version: 2
Duplex: full

As you can see this even tells us what version of software our neighbour is running. Sometimes you don’t want to tell people (like 3rd parties) what you are running so you can turn off CDP on the router, or just the interface that is connected to the 3rd party.

So with our first interface configured, I’m going to go and setup the rest of my interfaces, then I’m going to show an overview with the ‘sho ip interface brief’ command like this:

corertr1#sho ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 YES manual up up
FastEthernet0/1 unassigned YES NVRAM administratively down down
Ethernet1/0 YES NVRAM up up
Ethernet1/1 YES NVRAM up up
Ethernet1/2 unassigned YES NVRAM administratively down down
Ethernet1/3 unassigned YES NVRAM administratively down down
Ethernet1/4 unassigned YES NVRAM administratively down down
Ethernet1/5 unassigned YES NVRAM administratively down down
Ethernet1/6 unassigned YES NVRAM administratively down down
Ethernet1/7 unassigned YES NVRAM administratively down down

As you see this shows the interfaces that are capable of having an ip address, and which ones do have an ip address.  Now let’s configure the ‘WAN’ router with an IP address so we can do a ping. From dynagen bring up the corewan1 console:

=> console corewan1

You will probably want to setup the router much like how we did in the prior page.

corewan1#config t
Enter configuration commands, one per line. End with CNTL/Z.
corewan1(config)#int fa0/0
corewan1(config-if)#desc WAN network
corewan1(config-if)#ip address

Notice that I gave it .6 not .5 as that would be a duplicate ip address!  CDP updates every 60 seconds by default, so after a minute this is what we now see from corertr1:

corertr1#show cdp neighbors detail
Device ID: corewan1
Entry address(es):
IP address:
Platform: cisco 7206VXR, Capabilities: Router
Interface: FastEthernet0/0, Port ID (outgoing port): FastEthernet0/0
Holdtime : 124 sec

Version :
Cisco Internetwork Operating System Software
IOS ™ 7200 Software (C7200-JS-M), Version 12.2(31), RELEASE SOFTWARE (fc2)
Technical Support:
Copyright (c) 1986-2005 by cisco Systems, Inc.
Compiled Thu 11-Aug-05 15:57 by tinhuang

advertisement version: 2
Duplex: full

Notice we now see the peer ip addres!  Now we can ping.


Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/21/24 ms

Although it may not be important now, but ping has an incredible featureset on cisco routers.  Simply type in ping this time, and be amazed.  Google will lead you to what all these options mean for now, but just be aware this is one of the reason people buy cisco routers.

Protocol [ip]:
Target IP address:
Repeat count [5]:
Datagram size [100]: 1000
Timeout in seconds [2]: 3
Extended commands [n]: y
Source address or interface:
Type of service [0]:
Set DF bit in IP header? [no]: y
Validate reply data? [no]: y
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]: y
Sweep min size [36]: 500
Sweep max size [18024]: 600
Sweep interval [1]:
Type escape sequence to abort.
Sending 505, [500..600]-byte ICMP Echos to, timeout is 3 seconds:
Packet sent with a source address of
Packet sent with the DF bit set
Reply data will be validated
Success rate is 100 percent (505/505), round-trip min/avg/max = 16/21/44 ms

Now that we can ping, we can even telnet to the wan router from the core router.

Trying … Open

|\ _,,,—,,_
/,`.-‘`’ -. ;-;;,_
|,4- ) )-,_..;\ ( `’-‘
‘—”(_/–‘ `-‘\_) Welcome to the corewan1

Authorized users ONLY!!!!

User Access Verification


We can even check to see who is ‘on’ the router with the who command.

Line User Host(s) Idle Location
0 con 0 idle 00:00:17
* 2 vty 0 idle 00:00:00

Interface User Mode Idle Peer Address


Wasn’t that simple?

Physical network topologies

This is part of my on going thing about cisco networking.

I guess I can go on about various serial port standards from the good old fashioned RS-232, and V.35.  Not to mention things like T1/E1/J1’s with HDLC, Frame relay, Ethernet, TokenRing, ATM….


And of course various virtual technologies like VPN’s, and tunnelling.


So for now, my placeholder will just contain one little gem of wisdom about V35 cables.

A bunch of V35 cables

A bunch of V35 cables

When you are connecting V35’s remember to slowly screw them in, and try to screw both screws in at the same time, or a little bit on each side.  If you try to screw one side in all at once, you could break the screw, or worse it’ll help you strip the other screw trying to go in as it’ll be all lopsided.


Frame Relay

Frame relay is a great ‘slow’ networking cloud solution from back in the day.  For people who were going to deploy global WAN solutions that were going to be sub T1/E1 speeds, frame relay was the way to go.  You would simply get a T1 port installed in each of the sites, then the provider will then create PVC’s from each of the sites.  What is great is you can (theoretically) quickly provision new sites, and change service classes as needed.  Sadly for frame relay it is hampered by the port speed being only a T1/E1, limiting it to 1.5MB/2MB.  But heck it is from the mid 1980’s, so what do you expect?


On the Dynamips / Dynagen simulation configuring frame relay is pretty simple.  The Frame Relay switch is already configured in my example here:

[FRSW F1]]
1:102 = 2:201
1:103 = 3:301

Which just specifies that on my WAN router pvc 102 goes to pvc 201 in New York, and pvc 103 goes to pvc 301 in Hong Kong. For simplicity sakes, all the physical serial ports are S1/0. With this in mind, let us first configure the physical interfaces in all the routers.

So the first step is to set the encapsulation on the serial interface to frame-relay.  Then turn the interface on.

nycrtr1#config t

Enter configuration commands, one per line. End with CNTL/Z.
nycrtr1(config)#int s1/0
nycrtr1(config-if)#encapsulation frame-relay
nycrtr1(config-if)#no shut

Now we wait for the interface to transition.

00:18:43: %LINK-3-UPDOWN: Interface Serial1/0, changed state to up
00:18:54: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to up

Now we can check to see if the router see’s the PVC going to the core wan router.

nycrtr1#sho frame-relay pvc

PVC Statistics for interface Serial1/0 (Frame Relay DTE)

Active Inactive Deleted Static
Local 0 0 0 0
Switched 0 0 0 0
Unused 1 0 0 0


input pkts 0 output pkts 0 in bytes 0
out bytes 0 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 0
out bcast pkts 0 out bcast bytes 0
switched pkts 0
Detailed packet drop counters:
no out intf 0 out intf down 0 no out PVC 0
in PVC down 0 out PVC down 0 pkt too big 0
shaping Q full 0 pkt above DE 0 policing drop 0
pvc create time 00:02:12, last time pvc status changed 00:02:02

Looks good!

Now lets configure the DLC on the frame relay sub interface

nycrtr1#config t
Enter configuration commands, one per line. End with CNTL/Z.

nycrtr1(config)#int s1/0.201 point-to-point
nycrtr1(config-subif)#frame-relay interface-dlci 201
nycrtr1(config-subif)#ip address


Now for the ultimate test once the other side is configured.

corewan1#sho run int s1/0.102
Building configuration…

Current configuration : 140 bytes
interface Serial1/0.102 point-to-point
description NewYork
ip address
frame-relay interface-dlci 102


Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/20/24 ms

And there we go, our Frame relay is up!


Inspired from this video, I have to admit I’m really impressed how GNS3 can now network between dynamips router instances, and Qemu … So I grabbed an old IOS version from a 7200, and fired up Qemu with NT 4.0 and built a super simple network.  Because it won’t let you hotplug cables between hosts, I figured I’d just go ahead and add switches everywhere.  So bottom line is that I setup a super simple network, and I can ping/telnet to the routers from NT.  This could even be used to build more complicated networks, but as always people seem to get more excited about doing ‘pings’ through the network, and overlook actual USER traffic…

GNS3 uses a custom build of Qemu 0.11.0, which I may have to feel the need to modify it for some control-alt-delete fun, along with making sure the ISA NE2000 is on an agreeable port/IRQ.