This document discusses some of the most frequently asked questions
(FAQs) on the Compatible Systems - IP Networking.
Technical Tips Conventions for more information on document
My connection to the Internet seems to be set up correctly, and I can
ping from the router to any node on the Internet, but none of my other hosts
can access or be accessed by the Internet. Why?
A. First, check that the hosts on your network have their gateway or
default router address set to the IP address of the Ethernet port of the
router. This workstation parameter tells the workstation where to send packets
that are not addressed for its local network.
If the gateway addresses are set correctly, your ISP must not have a
network route set up to your network.
I used the standard configuration of the router with only one change at
the start: Ethernet IP number 18.104.22.168. From a workstation
(22.214.171.124), I pinged the router, and it responded. As soon as I assigned
the IP number 126.96.36.199 to the WAN port, I was unable to ping the Ethernet
port, anymore. I have tried different subnet masks with the same result. The
router dials and connects fine to my server. I can ping the WAN port
(188.8.131.52) from my server, but I cannot ping the Ethernet port
(184.108.40.206) from anywhere. From my server, I cannot ping the workstation
(220.127.116.11) connected to the router, either.
A. The router must have different networks on each port in order to route
between the ports. In order to use an IP address for the WAN port of the router
(called "numbered interface" in CompatiView), you must use an address from a
different IP network than the IP network(s) on any other interface on the
IP address 18.104.22.168 and 22.214.171.124 are on the same network
as long as they both have a class C subnet mask of 255.255.255.0. The router in
this case does not route between the Ethernet port and the WAN port.
In this scenario, you need to use a 255.255.255.192 subnet mask on
EVERY device on the network. The Ethernet subnet is then 126.96.36.199
through .255 with usable host addresses between 188.8.131.52 through .254.
The WAN subnet is then 184.108.40.206 through .127 with usable host addresses
between 220.127.116.11 through .126.
Most routers configured for PPP can use an unnumbered interface, where
an IP address is not required for the WAN ports. Check with your ISP for this
Do the RISC Routers 3500R and 3800R support multiple class C addresses?
For instance, on the 3800R, can each of the 12 ports have a separate class C
A. Not only CAN they have separate IP network numbers, they MUST have
separate IP network numbers since that is the definition of a router. These can
be class A, B, C, or subnets thereof.
Is remote router administration supported through a PPP
A. You can remotely administer Compatible Systems routers with CompatiView
for Windows through a remote PPP connection.
Can you recommend a software package that monitors the traffic on
Compatible Systems routers?
A. In order to watch TCP/IP packets on your Macintosh, you can use the
packet monitoring packages, EtherPeek from the AG Group
NetMinder Ethernet from Neon Software.
They are independent of the router since they run on your Macintosh.
In order to watch TCP/IP packets on your UNIX or Windows NT, you can
use Multi-Router Traffic
. Additionally for Windows NT, there is
SNMPc from CastleRock
I was originally assigned a block of 64 IP addresses from my ISP. In the
next 2 months I will be out of addresses. If I have my provider assign and
route an additional block do I need to make changes to my router
A. Yes, one of two methods can be used.
If your new addresses are simply an expansion of your old subnet,
with a mask of 255.255.255.128, you must change the mask and broadcast address
in the configuration of the router and in the currently configured equipment
that has an old address.
If you are given a totally new subnet, it can be configured on the
router if you add a new subinterface. The router routes between the two subnets
on the LAN, and the addresses do not have to be changed on currently configured
Note: The MicroRouter 1000R and the RISC Router 3000E do not support
subinterfaces. If you have a PPP WAN connection, the Microrouter 900i must use
router code v4.10B6 in order to support subinterfaces. This is an Interim
software release and does not function in all instances.
If you have a Frame Relay WAN connection, do not enter any mappings in
the DLCI database. The 900i goes into a boot loop if you do. The 900i and the
router on the other side of the Frame Relay link use IARP to dynamically pick
up DLCI and IP address mappings.
I currently have a 2600i with a T1 connection to my ISP. Is it possible
to use the second V.35 port to connect with one of our vendors over another T1
in order to allow them to have access to the Internet through
A. Yes, but the second V.35 port connection to your vendor over another T1
must be a different IP subnet obtained from your ISP, or you can use IP Proxy
ARP and a subnet of your current Class C to another WAN router at the site of
I currently have two Compatible Systems routers that route to each other
at separate sites. Can one of them be configured to route TCP/IP packets to
another site, as well?
A. The routers can route to more than one place if the routing tables have
the entries. These entries are made up of directly connected routes (based on
the Ethernet and WAN configurations), dynamic routes (received through RIP-1,
RIP-2, OSPF or BGP4), and static routes (added by you). You can add any static
routes that you wish as long as the gateways are attached to one of the
directly connected networks.
Can I configure my router with the Class C network address of 192.0.0.0
to a PPP terminal?
A. This is a reserved Class C IP network. You are able to route this on a
private network, but you are not able to access the Internet. The private Class
C IP addresses allocated by the Internet Assigned Numbers Authority (IANA) are
from 192.168.0.0 to 192.168.255.255. You can choose to use any of those Class
Cs if you have a private net that does not go out to the Internet. If you need
to access the Internet, you must have routable addresses, most likely assigned
by your ISP.
I have been able to get a router configured and operational to the point
where I can Telnet to the router, but nothing is able to go beyond it.
A. If the router is the only one on the network or is the Internet gateway
for the network, and you have an unnumbered WAN, set a static route with the
destination of 0.0.0.0, subnet mask of 0.0.0.0, gateway of WAN A, a metric of 1
and leave RIP disabled.
If the router is the only one on the network and you have a numbered
WAN, set a static route as mentioned but with a gateway of the IP address of
the WAN port in use.
If the router is not the Internet gateway for the network, set a static
route as mentioned but with a gateway of the IP address of the next upstream
router. In most cases, this is the Internet gateway router.
The router is set to do RIP. Since the router has been rebooted a few
times, the static routes are not loaded.
A. The static routing table is stored in the flash EPROM of the router.
You can see the routes you entered in Command Line "show ip routing" under
"Configured IP Routes" or "Edited IP Routes."
It is usually easier to run either static routes or RIP, but they can
certainly be used in combination. If you get a route from RIP that you have
already entered as a static route, you cannot see the route in the static route
I have a situation where the ISP for my router takes down the link after
20 minutes inactivity. I have a syslog machine that collects information. I
have tried to use RIP to prevent inactivity, but it seems to have no effect
since I do not pick up routing info from the terminal server into which I am
dialed. Is there some other way that I can force activity on the
A. RIP does the trick, as long as it is set for periodic, rather than the
default, which is triggered. This can be set with Command Line or CompatiView
in the TCP/IP Routing section for the relevant WAN port.
The router sends RIP packets out the WAN port every 30 seconds. The
terminal server can or cannot keep the link up when it sees RIP packets. If it
does not, you have to write a cron script or use some other timer program to
send pings at a regular interval from a workstation on your local
Do Compatible Systems routers allow the IP Broadcast packets to pass
through the router to the remote LAN?
A. UDP Forwarding can be enabled on the router. This can be done in
CompatiView or through Command Line. This directs UDP broadcasts for DNS,
BOOTPS (DHCP), TFTP, NTP, NB_NS, or NB_DG to a server IP address across the
WAN. Refer to the Compatiview Management Software Reference
Guide or the Text-Based Configuration and Command Line
Management Reference Guide for more information.
How do I configure Macintosh Open Transport, so my workstations are
served their IP addresses from EtherRoute IIs?
A. Run the TCP/IP application in the Control Panels folder. When the
window opens, there is a "Connect via" popup at the top. Choose AppleTalk
(MacIP). The bottom of the window changes. If the router has been configured
for dynamic addresses, choose "Using MacIP Server" from the "Configure" popup
menu. If the router has been configured for static addressing, choose "Using
MacIP Manually" from the "Configure" popup menu and enter the IP addresses of
the Macintosh, router, and name server.