[Info-vax] Routing when using two interfaces/networks.

[Jan-Erik Soderholm]

Hi.
We have some hard-to-identify network problems at
a site and I'm now thinking that it might have something
to do with how the routing is setup in the VMS system.

The VMS system (the "prod" system) has two interfaces :

$ tcpip sh inter

Interface   IP_Addr         Network mask

  LO0        127.0.0.1       255.0.0.0
  WE0        193.183.98.2    255.255.255.0
  WE1        10.32.137.1     255.255.255.0


The 193.183.x.x is the "old" network that will be removed
anytime(tm). The 10.32.x.x network is where most of the other
stuff (term-servers, PC-clients and so on) are. Note that
most other equipment on 10.32.x.x are on other subnets then
10.32.137.x. The only other host on the 10.32.137.x are mainly
the other VMS systems. All "user" equipment are on other
10.32.x.x networks.

The current routing looks like this :

$ tcpip sh route

                        DYNAMIC

Type           Destination                    Gateway

AN    0.0.0.0                         193.183.98.251
AN    10.32.137.0/24                  10.32.137.1
AH    10.32.137.1                     10.32.137.1
AH    127.0.0.1                       127.0.0.1
AN    193.183.98.0/24                 193.183.98.2
AH    193.183.98.2                    193.183.98.2
st
$ tcpip sh route/perm

                        PERMANENT

Type           Destination                    Gateway

PN    0.0.0.0                         193.183.98.251


The "dev" system has only one interface and looks like this :

$ tcpip sho inter

Interface   IP_Addr         Network mask

  LO0        127.0.0.1       255.0.0.0
  WE1        10.32.137.3     255.255.255.0

$ tcpip sh rout

                              DYNAMIC

Type           Destination                   Gateway

AN    0.0.0.0                          10.32.137.254
AN    10.32.137.0/24                   10.32.137.3
AH    10.32.137.3                      10.32.137.3
AH    127.0.0.1                        127.0.0.1

$ tcpip sh rout/perm

                              PERMANENT

Type           Destination                   Gateway

PN    0.0.0.0                          10.32.137.254


The "problems" we are seeing are e.g. :

- Troubles ("hangs") when FTP copying from "prod" to "dev".
- Intermittent slow access from PC clients.

My guess is that the disturbances are due to the fact that all
routing goes through the 193.183.98.251 gateway, even between
different 10.32.x.x subnets, right ? And that the solution
probably would be to simply move the default router from
the 193.183.98.251 gateway to the 10.32.137.254 gateway on
the system with two networks ?

Jan-Erik.