New TCP Analyzer.

Post by **Philip** » Mon Mar 05, 2001 6:48 pm

We are testing a new tool that anallyzes your TCP parameters and sends back the information (such as effective RWIN, MTU, etc..), as well as some recommendations.

The TCP Analyzer is currently in Alpha-testing pariod, please check it out and report any bugs/problems/observations to the board, or you can email me directly at philip@speedguide.net .

The tool was designed by a good friend of mine and myself, we're still working on it.

Here's a link, all feedback is appreciated:
http://forums.speedguide.net/optd.shtml

Lobo · Post by **Lobo** » Mon Mar 05, 2001 7:03 pm

This is as cool as grits!!!!!!!!!!!!!!!

Duzmor · Post by **Duzmor** » Mon Mar 05, 2001 7:09 pm

Philip: Looks Great - Tells all - Good Job

Duzmor

Lobo · Post by **Lobo** » Mon Mar 05, 2001 7:14 pm

Anyway to get pings in there, it is cool

Cyke · Post by **Cyke** » Mon Mar 05, 2001 7:20 pm

Neat!

Post by **Philip** » Mon Mar 05, 2001 7:27 pm

Originally posted by Lobo:
Anyway to get pings in there, it is cool

That's reserved for another similar tool we're planning on

Lobo · Post by **Lobo** » Mon Mar 05, 2001 7:40 pm

Like Flint Westwood said, make my day, cool

cablenut · Post by **cablenut** » Mon Mar 05, 2001 7:59 pm

Phillip thanks for making a tweak tester that actually works!! Very good job it is easy for me to diagnose other people's problems and mine also... thanks again.

tekelberry · Post by **tekelberry** » Mon Mar 05, 2001 8:29 pm

Phillip,
you give a reccomendation about my MSS. You never said anywhere on the registry tweak section about MaxMSS, just MaxMTU. Could you please explain?

HalfLifer · Post by **HalfLifer** » Mon Mar 05, 2001 9:23 pm

It said my RCW is 65535 when its really 373330?

Lobo · Post by **Lobo** » Mon Mar 05, 2001 9:31 pm

Hi I would take tweak test at dslr and if it says 65535, you need to download and install Vtcp386 Fix patch from patch page

Post by **Philip** » Mon Mar 05, 2001 9:56 pm

Originally posted by tekelberry:
Phillip,
you give a reccomendation about my MSS. You never said anywhere on the registry tweak section about MaxMSS, just MaxMTU. Could you please explain?

MSS is calculated automatically by Windows to MaxMTU - 40 ... Microsoft has no reference to setting MSS in the Registry.

You can usually change MSS by changing MaxMTU.

Post by **Philip** » Mon Mar 05, 2001 9:59 pm

Originally posted by HalfLifer:
It said my RCW is 65535 when its really 373330?

The TCP Analyzer is actually a server that captures SYN - SYN/ACK packets and extracts the header from your TCP packet. The results you see are what's actually advertized as your RWIN.

Dakota · Post by **Dakota** » Mon Mar 05, 2001 10:49 pm

Yeah, Baby!!

This is awesome!!! A definite three thumbs up!

cablenut · Post by **cablenut** » Mon Mar 05, 2001 11:26 pm

HalfLifer if you think your ScaledWindow gets used by every server your wrong. If you turn on TCP1323Opts Windows will send a request for the remote server in a ACK packet to use ScaledWindows if the remote server doesn't use ScaledWindows (which majority of them don't, hell majority of them use less then 64240 RWIN's) then your out of luck which then your Window is scaled down to 65K or less apporiatly.

minir · Post by **minir** » Mon Mar 05, 2001 11:44 pm

Hi Philip

Very Clean in presentation

Fast in deployment

concise in terms of explanation

thorough in evaluation

easy to implement

Nice, very professional

regards minir

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 12:29 am

Weird, I set the MTU in my PC to 1496, but yet the TCP Analyzer shows it up as 1500

, I'm a newbie when it comes to this stuff

TCP options string = 020405b0010303030101080a000000000000000001010402

MTU = 1500

MTU is at optimal value

MSS = 1456

Default Receive Window (RWIN) = 373760
RWIN Scaling (RFC1323) = 3 bits
Unscaled Receive Window = 46720

For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
256256 (MSS x 44 * scale factor of 4)
192192 (MSS x 44 * scale factor of 3)
128128 (MSS x 44 * scale factor of 2)
64064 (MSS x 44)

bandwidth * delay product:

Your RcvWindow limits you to: 29900.8 kbps (3737.6 KBytes/s) @ 100ms
Your RcvWindow limits you to: 14950.4 kbps (1868.8 KBytes/s) @ 200ms
Your RcvWindow limits you to: 5980.16 kbps (747.52 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = 1

Time to live = 51 hops

Timestamps (RFC1323) = 1

Selective Acknowledgements (RFC2018) = 1

IP type of service = 0

BTW, great Analyzer Philip, You Rock

Also, going by my Analyzed Stats, do you guys have any recommendations so that I can tweak this badboy. I used the Speedcorp Win2K Tweak and I was just curious thanx

[ 03-06-2001: Message edited by: Prey521 ]

Post by **Philip** » Tue Mar 06, 2001 12:35 am

Thanks minir

Prey, do you use some router or any hardware that might modify your MTU ? MSS is shown at the correct value, it is strange. I'll check the code.

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 12:37 am

Originally posted by Philip:
Thanks minir

Prey, do you use some router or any hardware that might modify your MTU ? MSS is shown at the correct value, it is strange. I'll check the code.

Nope, this PC is not on my Router. I have it ICS'd with another PC in my room.

Post by **Philip** » Tue Mar 06, 2001 12:37 am

Also, does the IP shown on the results page show your correct IP ? I'm wondering whether it picks up a proxy server or something else along the way.

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 12:39 am

Originally posted by Philip:
Also, does the IP shown on the results page show your correct IP ? I'm wondering whether it picks up a proxy server or something else along the way.

Nope, IP does not show, also, I ran this test from the Client but the IP also does not show up on the Host PC as well.

Post by **Philip** » Tue Mar 06, 2001 12:40 am

You mean you don't see anything on the IP line below the title ?

"TCP properties for IP = xxx.xxx.xxx.xxx"

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 12:47 am

Originally posted by Philip:
You mean you don't see anything on the IP line below the title ?

"TCP properties for IP = xxx.xxx.xxx.xxx"

Whoops, Yeah, it shows up, i didnt see that up there LOL. It shows the IP of the cable modem 24.168.xxx.xxx

[ 03-06-2001: Message edited by: Prey521 ]

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 1:16 am

OK,

The NIC that is on the Host PC that's connected to the Client has an MTU of 1500. Would changing that NIC's MTU to 1496 correct this?

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 1:35 am

K,

I set the NIC on the Host to an MTU of 1496, also on the NIC that is connected to the modem, and it still shows up on the Analyzer test as 1500 on both machines. Is anyone else using ICS gettin there MTU registered correctly using the Analyzer?

[ 03-06-2001: Message edited by: Prey521 ]

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 2:07 am

DSLReports Tester shows both machines MTU as 1496, just thought that you might wanna know that

dannjr · Post by **dannjr** » Tue Mar 06, 2001 2:18 am

Philip this thing is great in more ways than I could describe.. it would take its own page with how much I like it...
However and I noticed and I'm sure you want to read the ugly side to... I have this blindness problem ever since I'v been working with cablenut

hehehe Well I have to sdjust the page to 800x600 when you do the test goes off the page you might want to resize the frame just a suggestion...
Now Im on PPPoE I use a router and I also get a reading of 1500 for MTU, but it gets the MSS right.. In fact it nails that number right on all the machines here...
Im gonna play with it some more later....
Thanks again...
Do some sniffs

If there s a particular way you would like me to do it let me know...

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 2:21 am

Originally posted by dannjr:
Now Im on PPPoE I use a router and I also get a reading of 1500

K, good, I'm not the only one then

Scoot · Post by **Scoot** » Tue Mar 06, 2001 7:12 am

Phillip,
I too get the 1500 MTU reading.
I have one pc with ZA. Correct IP, it is actually set at 1496 verified through registry and at Dslreports. The MSS shows correctly at 1456.
Sure is fast, good job.

Lobo · Post by **Lobo** » Tue Mar 06, 2001 7:26 am

I'm not picking, info is all, I too set my MAXMTU at 1496, it read 1500, dslr read 1496
Your program read MSS as 1456, which would be right and I would agree with Dannjr, but a great start, keep up de good stuff

Post by **Philip** » Tue Mar 06, 2001 10:55 am

Well, seems there are still a couple of bugs we need to track down, thanks for the constructive feedback.

Post by **Philip** » Tue Mar 06, 2001 5:05 pm

The MTU bug should be fixed now, let me know if you're still getting any errors.

cablenut · Post by **cablenut** » Tue Mar 06, 2001 5:11 pm

The MTU is fixed it correctly states my router limited MTU/MSS very good.

blebs · Post by **blebs** » Tue Mar 06, 2001 5:16 pm

Just checked mine and now, MTU is incorrect. I have it at 1500 and the test shows it to be at 1512. Double checked it with DSL reports and in the registry. Unless I'm missing something here, it came up incorrect where before everything was right on que.

[ 03-06-2001: Message edited by: blebs99 ]

Easto · Post by **Easto** » Tue Mar 06, 2001 5:19 pm

So what exactly do: "The page cannot be displayed" mean?

Post by **Philip** » Tue Mar 06, 2001 5:20 pm

blebs99, please post your entire results so I can troubleshoot it. Thanks.

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 5:21 pm

Hmmmmm, on the WinME Host machine it reports my MTU as 1508 and on my Win2K the page just crashes

Post by **Philip** » Tue Mar 06, 2001 5:21 pm

Easto, it means the Analyzer server is down for some reason, it should be back up in a minute or so.

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 5:22 pm

These are the results from the WinME host:

TCP options string = 020405b0010303030101080a000000000000000001010402

MTU = 1508

Your MTU value seems to be larger than the Ethernet specs, consider lowering it to 1500 or 1496.
If you're on DSL that uses PPPoE, the maximum allowed packet size is 1492.

Prey521 · Post by **Prey521** » Tue Mar 06, 2001 5:24 pm

K, i got it to run on the Win2k client, but it gave me the same error as specified above, but I know that the MTU's are setup correctly on my PC's.

[ 03-06-2001: Message edited by: Prey521 ]