Routing Issue, 2nd Network

[Jim Mallett]

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

[Sundar_7]

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.

[Patrick Wallek]

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]

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.

[Sundar_7]

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.

[Jim Mallett]

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

[John Kittel]

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]

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]

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

[Jim Mallett]

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.

Providing I survive the Red Sox parade!!

YEEEEE HAAAAAAAAA, Go Sox!

[Sridhar Bhaskarla]

Jim,

You don't have to distrub HOSTA and HOSTb's configuration. It's between Hostc's built-in lan and the switch port. Since you can't set the speed to the built-in lan interface of hostc, I suggest you check the speed on the 3com switch. My guess would be that it might have been hardset to 100 Full Duplex Auto-off. Set it to AUTOON and it may fix the issue.

-Sri

[Jim Mallett]

Sri,

The switch isn't configurable, it's auto-sensing and it's automatically sensing the 10mb connection from HostC. HostC is actually getting through the switch to a router across a T1 to the other network and communicating without issue.

I've tried HostA and HostB at 100FD/100HD/10FD/10HD and they just don't want to see anything but eachother, regardless of the settings.

Jim

[Sridhar Bhaskarla]

Jim,

When you said it is communicating to the router means it is through your 172 network?. Means you have few more hosts other than HOSTA and HOSTB with the interfaces on 172.31.4 network?. What is the result you get when you ping to the broadcast address on HOSTC?.

ping 172.31.4.255

Do you get multiple responses?. If so, then the connectivity is fine from HOSTC to switch. If you get a response only from itself (4.20), then it is not passing through your switch.

-Sri

[Jim Mallett]

When I ping the broadcast address for 172 from HostC it can see itself and the router that connected to the the switch. I can also ping individual hosts that exist on the other side of the router in 172. HostC has been running for years without connectivity issues.

When I ping the broadcast from HostA and HostB they only see eachother. HostA and HostB recently had the NICs added and I just configured them for the 172 network. These 2nd NICs on all three hosts connect to a switch. The switch also has a router connected to it that goes to a CSU/DSU across the WAN to our sister company.

I initially thought it was a routing issue or a port issue on the switch, but the fact that HostA and HostB talk to eachother, and HostC and router talk shows that ports are working.

I know 10FD and 100FD will have issues talking directly, but I thought when there was a device in the middle, like a switch, that wasn't an issue. Just to test, I set HostA at 10HD and HostB at 100FD and they communicated just fine with the switch in the middle (on the 172 network).

I'm going to to set my laptop IP to a static 172 address and direct connect it to the switch in the morning. It will be interesting to see which hosts I can connect to.

As far as the router goes, I have been assured there is no IP filtering going on, so any host I connect to the switch should be able to get to and thru the router. Regardless, the problem seems to be before the router because HostA/B can't see HostC and they are all on the same switch.

I'm heading to sleep now but I do appreciate your time and ideas so far regarding this.

Jim

[Jim Mallett]

Get burned by the networking department once, shame on them. Get burnt by them twice, shame on me.

I plugged my laptop into the switch today to test it and noticed there was no activity on any of the other ports, there should have been considerable activity. I followed the cables back to find them going to different hosts. It was the wrong switch, or better put, it was marked incorrectly.

All worked great once I plugged into the right one.

Jim