Problem accessing full range of ip addresses

[Peter Klee]

We have an Alpha DS20 running OpenVMS 7.3-2, with an ip address of 192.168.1.1 and with a subnet of 255.255.252.0, as shown below. This Alpha uses Multinet v4.4 for TCP/IP services. From this subnet mask we are using, we should be able to ping PCs on the 192.168.0.n to 192.168.3.n range, but oddly from the Alpha we can only ping PCs with ip addresses in the 192.168.1.n subnet.

The PCs we are trying to ping all have the 255.255.252.0 subnet mask.


KIR$ mu config

MultiNet Network Configuration Utility V4.4(104)

[Reading in MAXIMUM configuration from MULTINET:MULTINET.EXE]

[Reading in configuration from MULTINET:NETWORK_DEVICES.CONFIGURATION]

NET-CONFIG>show

Interface Adapter CSR Address Flags/Vector

--------- ------- ----------- ------------

se0 (Shared VMS Ethernet/FDDI) -NONE- -NONE- -NONE-

[TCP/IP: 192.168.1.1, IP-SubNet: 255.255.252.0]

[VMS Device: EIA0, Link Level: Ethernet]





Official Host Name: KIR

Timezone: MST

Timezone Rules: US/MOUNTAIN

Load UCX $QIO driver: TRUE

Load PWIP (Pathworks) driver: TRUE

NET-CONFIG>



Our routing table has a default gateway, which is a firewall also using the 255.255.252.0 mask, and if we remove the default gateway from the routing table, it doesn’t matter, we still can’t ping PCs on any subnet except 192.168.1.n.



KIR$ MU SHO/ROUTE

MultiNet IP Routing tables:

Destination Gateway Flags Refcnt Use Interface MTU

---------- ---------- ----- ------ ----- --------- ----

172.26.254.0 192.168.1.5 Up,Gateway,H 0 0 se0 1500

LOCALHOST LOCALHOST Up,Host 3 15697 lo0 4168

156.55.244.137 192.168.1.179 Up,Gateway,H 0 0 se0 1500

170.186.14.205 192.168.1.5 Up,Gateway,H 1 7174 se0 1500

170.186.50.145 192.168.1.5 Up,Gateway,H 0 0 se0 1500

156.55.254.21 192.168.1.179 Up,Gateway,H 1 4548 se0 1500

199.186.98.215 192.168.1.5 Up,Gateway,H 0 0 se0 1500

167.16.68.180 192.168.1.5 Up,Gateway,H 0 0 se0 1500

DEFAULT-GATEWAY 192.168.1.161 Up,Gateway 0 0 se0 1500

192.168.1 KIR Up 84 7007332 se0 1500



MultiNet IPX Routing tables:

Destination Gateway Flags Refcnt Use Interface MTU

---------- ---------- ----- ------ ----- --------- ----

KIR$



When I try a traceroute to a PC on the 192.168.1.n subnet, it comes right back. But if I try a traceroute to a PC on 192.168.2.n (or 192.168.0.n for that matter) the traceroute hangs….



KIR$ mu traceroute 192.168.1.199

traceroute to 192.168.1.199 (192.168.1.199), 30 hops max, 40 byte packets

1 192.168.1.199 (192.168.1.199) 8 ms 8 ms 7 ms

KIR$



KIR$ MU TRACEROUTE 192.168.2.113

traceroute to 192.168.2.113 (192.168.2.113), 30 hops max, 40 byte packets

1 *

Interrupt

KIR$


The PC with the IP address 192.168.2.113 can ping all devices on 192.168.0.n, 192.168.1.n, 192.168.2.n, and 192.168.3.n, except for the Alpha. The Alpha doesn’t respond to pings from PCs that are on 192.168.0.n, 192.168.2.n, and 192.168.3.n. The Alpha is only responding to devices on the 192.168.1.n despite the subnet mask it is using.


We’ve been unable to determine what’s wrong here, but it’s as if the Alpha thinks it’s using a 255.255.255.0 subnet mask. The Alpha was originally configured with this ip address and mask and has been rebooted since.


Any ideas what’s wrong here?


Any thoughts are appreciated.

[Wim Van den Wyngaert]

I don't know about multinet but will try to answer for ucx. Setup seems ok to me.

1) if you do ucx sho arp after the PC pinged. Is the PC in it ?
2) is there any limitation on the interface show in ucx show comm/sec ?
3) try a tcpip trace. May be the alpha is answering but the answers don't get to the PC.
4) check the protocol counters for errors (ucx show prot)

Wim

[Peter Klee]

I have since found that the system in question is not using the correct ip broadcast address (is 192.168.1.255; should be 192.168.3.255). Also, there is a discrepancy in the subnet mask being used, as shown below.

I will work on correcting these.

Thanks for your insights.

KIR$ mu show/int se0

Device se0: flags=863

VMS Device = EIA0

IP Address = 192.168.1.1

IP Sub-Net Mask = 255.255.255.0

IP Broadcast Address = 192.168.1.255

No common links defined

Average 702 bytes out, 874 bytes in per second

Average 2 packets out, 3 packets in per second

KIR$



KIR$ mu config

MultiNet Network Configuration Utility V4.4(104)

[Reading in MAXIMUM configuration from MULTINET:MULTINET.EXE]

[Reading in configuration from MULTINET:NETWORK_DEVICES.CONFIGURATION]

NET-CONFIG>show

Interface Adapter CSR Address Flags/Vector

--------- ------- ----------- ------------

se0 (Shared VMS Ethernet/FDDI) -NONE- -NONE- -NONE-

[TCP/IP: 192.168.1.1, IP-SubNet: 255.255.252.0]

[VMS Device: EIA0, Link Level: Ethernet]





Official Host Name: KIR

Timezone: MST

Timezone Rules: US/MOUNTAIN

Load UCX $QIO driver: TRUE

Load PWIP (Pathworks) driver: TRUE

NET-CONFIG>exit

[Configuration not modified, so no update needed]

KIR$

[Antoniov.]

Peter,
welcome to vms forum.
I don't know multinet but reading your post I understand you have a running interface with 192.168.1.1 and 255.255.255.9 netmask, while you have a configurated but not active netmask. I guess you have to do something like restart multinet.

Antonio Vigliotti

[Peter Klee]

Thanks for your thoughts.

[Bob Talbot]

Peter,

The use of 255.255.252.0 with 192.168.1.1 is not supported in Multinet 4.4, as versions of Multinet prior to Multinet 5.0 do not support a class C address (192.168.1.1) using anything less than a class C subnet mask (255.255.255.0).

I thought I'd add that tidbit of information here in case others came across this scenerio.

Have a nice day.

Bob