Need help with LocalDirector

charles.combs · ‎01-17-2003

I'm trying to setup a performance test environment with an LD 430. My configuration is:

client PC 10.1.10.200

|

3Com Switch Vlan 2

|

LD 430 (real 10.1.10.2) 10.1.10.100 (Virtual)

|

Same 3Com Switch Vlan 1

|

Web Servers |

(real 10.1.10.140) |

(real 10.1.10.141) |

From my client PC, I can ping the virtual IP address. From the LD, I can ping all of the real IP's and none of the virtual IP's. From the web servers, I can ping the virtual IP.

I receive "Could not open a connection to host: Connect failed" when trying to reach the virtual IP using "telnet 10.1.10.100".

On the LD:

Real Machines:

No Answer TCP Reset DataIn

Machine Connect State Thresh Reassigns Reassigns Conns

wildcat:80 0 IS 8 0 0 0

liberty:80 0 IS 8 0 0 0

Virtual Machines:

Machine State Connect Sticky Predictor Slowstart

VIRTUAL-PERF:80:0 IS 0 0 leastconns roundrobin*

This is setup for port 80 at this time. I've also setup a virtual for telneting to the real servers and receive the same response.

Show syslog command only shows the transistion from slowstart to leastconn. I thought it might be a bridge loop, since I'm using the same 3Com switch, so I placed the client and LD interface 0 on a separate hub with no change in the symptoms.

Any assistance would be greatly appreciated. I've beaten my head on this all week with no resolution in sight.

TIA

d.parks · ‎01-17-2003

Can you ping the reals from your PC? You may want to try "no-secure" and "ping-allow" for the interfaces in use.

Your best bet would be to throw a protocol analyzer on the connection to see what the traffic is actually doing. Verify ARP is working, L2 addresses are correct etc.

charles.combs · ‎01-17-2003

No, from the client, I cannot ping the real server IP's. On the LD, the show bridge and show arp commands display the correct information for each interface. Could it be possible, since I don't have a default route set on the LD, (there is no router to point to), that this could be part of the problem?

I wish I had a protocol analyzer! We're just a small development shop, so I can't justify the cost of one of them. :-(

d.parks · ‎01-17-2003

If you add the "ping allow" and "no secure" commands for both of the Local Director interfaces to your configuration, it should enable you to ping from your PC. no-secure will also allow you to telnet or browse directly to the servers.

This will verify that the bridging path to and from the servers is working and will verify that the PC and server configurations are working as expected.

If this works then the problem has to be with the virtual to real functionality somehow.

If this does not work, then there is some sort of L2 problem that needs to be addressed.

The default route should not be required in this scenario assuming that they are configured for the same subnet.

There is a free protocol analyzer available that works fine for this sort of thing. Check out Ethereal. It's an open-source linux program that has been ported to windows. I use it on my machine for simple things like this when I don't feel like getting out the SnifferPro laptop.

charles.combs · ‎01-17-2003

Thanks for the info! The ping-allow and no secure were already set on the interfaces, yet the PC cannot get, via ping or telnet, to the real servers. I'll start looking at the L2 information after I download the analyzer.

Any clues as to what to look at first for L2 problems?

Tanks again!

d.parks · ‎01-17-2003

If the show ARP and show bridge info looks right, I guess I'm not sure what the problem would be. It seems that the LD just isn't bridging period.

I've switched most of our load balancing to the CSS's, so I haven't worked with LD's in awhile. I did look at my one remaining pair of LD's to see if anything stood out configuration-wise, but I didn't see anything too helpful.

Hopefully, a trace will shed some light.

charles.combs · ‎01-17-2003

Well, I've installed Ethereal. Cool tool, by the way. Capturing a telnet from the client to the virtual ip shows that the virt. ip, (with a MAC of the LD), is sending RST, ACK back to the client.

I've also downloaded the Unix version of Ethereal to run it on my webservers, but I don't think it's going to capture any info. I don't think the LD is actually bridging the requests from the client over to the real servers.

d.parks · ‎01-17-2003

What does the trace show when you try to go directly to the reals from your PC?

Also, have you tried pinging your PC from the server(s)?

Just for grins, you might want to try plugging the PC and one of the servers directly into the LD interfaces. (via. a crossover cable). Probably won't make a difference, but at least you could rule out the hub and/or switch as the source of the problem.

charles.combs · ‎01-17-2003

Interesting. Can't ping in either direction to the actual IP's. Capture of a telnet from the client to the server shows the following:

Client asks Who has 10.1.10.140

Server responses with it's MAC address

Client sends 3 SYN's Seq # = , ACK=0, Win=16384

Then nothing more.

Interesting that pings are allowed thru the LD, but don't work, yet the request for the MAC does get a response from the correct system.

I'll be going to the store tomorrow to buy some cross-over cables. Don't want to make them, since that could just induce another possible problem area.