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Routing Issue, 2nd Network

 
Jim Mallett
Honored Contributor

Routing Issue, 2nd Network

Is there anything different communicating between "ethernet" and "fast ethernet"?

I have three hosts that connect to our internal network (10.10) with no issue. All three hosts have second NICs that need to connect to another network (172.31.4). HostC has been connected for quite a while without issue. I just set up HostA and HostB and all three are now connected to the same switch. The two new hosts communicate fine, but neither will communicate with the original HostA.

I'm really not good at wording networking so there's an attachment for anybody that might want to point me in the right direction.
Basically HOST-A and HOST-B can see eachother without issue, but cannot see HOST-C.

Thanks....
Jim
Hindsight is 20/20
14 REPLIES 14
Sundar_7
Honored Contributor

Re: Routing Issue, 2nd Network

If all the three hosts connected to the same switch and configured to be in the same IP subnet, you should not require to add routing entries for the hosts to reach one and another.

When you say "cannot see HOST-C", do you mean not able to ping ?

I dont see any attachment in the post.
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Patrick Wallek
Honored Contributor

Re: Routing Issue, 2nd Network

Is the subnet mask consistent across all three hosts? It probably should be 255.255.255.0. If it is different on one or 2 that could be part of the problem.

Jim Mallett
Honored Contributor

Re: Routing Issue, 2nd Network

Here's a 2nd try w/ the attachment.

Sundar: The issue actually goes further, there is a router on the other side of the switch. That is why I made mention of the route statements. I have taken that completely out of the mix and tried to break it down to what appears to be the simplest problem. Right now HostA and HostB can ping eachother, but not HostC. HostC also see's the router on the other side of the switch.

Patrick: The netmasks on the 172 networks are all 255.255.255.0.

Hopefully the attachment goes.
Hindsight is 20/20
Sundar_7
Honored Contributor

Re: Routing Issue, 2nd Network

Jim,

How about a traceroute to HOST-C from HOSTA/B and post the output ?

Also try a linkloop from HOSTA to HOSTC's MAC address.

I am not really good at networking either..:-) but you can give this a try. Try assigning 172.31.4.20 to lan5 and 10.10.2.103 to lan0 of HOST-C. See if this helps

- Sundar.
Learn What to do ,How to do and more importantly When to do ?
Jim Mallett
Honored Contributor

Re: Routing Issue, 2nd Network

Communication thru the 10.10 NICS is fine with all three hosts. This issue is isolated to the 172 network.

Hmmmmm.... the linkloops HostA-->HostC and HostB-->HostC are failing too.

I don't think it's the cables because HostA and HostB communicate. Also, HostC communicates out thru thru the router.

It's a simple 3com 5-port switch so there's no port programming involved. All lights are green.

I can't take down any of the 10.10 adapters because they are production. I am going to try to changing the 172 network addresses and see what happens.

Jim

Hindsight is 20/20
John Kittel
Trusted Contributor

Re: Routing Issue, 2nd Network

in your attachment on host C there is a route for 10.10 with netmask 255.255.248.0 and gateway 10.10.2.103 ...

why does that not show the route as 10.10.0.0, - as it does for host A and B?

- John
Gennaro Tarone_2
Occasional Advisor

Re: Routing Issue, 2nd Network

The problem doesn't seem to be addressing. Buit you have mentioned asking the differences between ethernet & Fast ethernet. Have you checked the speed of the hosts? You can use SAM although I have seen SAM give false changes to the speed. Use the lanadmin command line (& not the lanadmin menu driven). The lanadmin command also depends on the ver of HP-UX you are running. 10.20 & some earlier releases of 11.0 use the NMID of the lan card while later ver use the lan#. to get the NMID do a lanscan. Otherwise you can use the lan#. the command is lanadmin -x # (the number symbol is either going to be the NMID if you have an earlier ver of HP-UX or the lan#) If your hosts have different speeds they will not see one another ie. HostA had 100 Half Duplex & HostC is at 100 Full Duplex. To set a host to 100 Full Duplex use lanadmin -X # 100FD.
Sridhar Bhaskarla
Honored Contributor

Re: Routing Issue, 2nd Network

Hi Jim,

Obviously your 10.10 network is fine. All three nodes can see each other through 10.10 network and also the router.

It looks like the cable/switch port where HOSTC's lan1 has been plugged into has a problem since linkloop is not working. What kind of interfaces are on HostA and HostB?. I see HostC is using built-in interface which is 10MB. Check if the speed on the switch port is not set to 100 Full Duplex.

-Sri
You may be disappointed if you fail, but you are doomed if you don't try
Jim Mallett
Honored Contributor

Re: Routing Issue, 2nd Network

Sri,all...

Everything definitely would point towards a port issue with HostC except that the host is the only one that actually see's thru the switch and router to the other network. It is the one host doing what I want. It is a 10mb card as you mentioned, it is a pretty old card. Sorry I don't have model numbers. The cards on HostA/B are fairly new hardware. They are both set at 100FD. I have changed each of them to 10HD and 10FD in an attempt to see if that would help.
When I run lanadmin -x on HostC it tells me it isn't supported.
The switch itself is a basic 3COM 5-port switch, so I'll try replacing that and testing any other ideas Saturday morning when I can take down the NICs.

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Hindsight is 20/20