@ work, shared DSL connection, Win98se, MTU Problem

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 11:08 am

TCP properties for IP = xxx.xxx.xx.x
Browser/OS = Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; Q312461)
Note: Read the FAQ if the above is not your IP address.

TCP options string = 020405910103030201010402

MTU = 1465
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1425
Maximum useful data in each packet = 1425, which equals MSS.
MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 256960
RWIN Scaling (RFC1323) = 2 bits
Unscaled Receive Window = 64240
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
501600 (MSS x 44 * scale factor of 8)
250800 (MSS x 44 * scale factor of 4)
125400 (MSS x 44 * scale factor of 2)
62700 (MSS x 44)

bandwidth * delay product:
Your RcvWindow limits you to: 10278.4 kbps (1284.8 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4111.36 kbps (513.92 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 52 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000

SG TCP Optimizer says

MaxMTU is 1500
TCP Receive Window: 256960
MTU Discovery: Yes
Black Hole Detect: No
Selective ACKs: Yes
Max Dup ACKs: 3
Time To Live (TTL): 64

Ive used Cable nut to put a general DSL tweak in.

IVe also done a search here and found plenty of people who couldnt modify their MTU's either and had to edit their registrys. Ive tried that and ive modified all I can, and cant find others.. The keys are just not there??

Can anybody help?

Lobo · Post by **Lobo** » Thu Aug 15, 2002 12:08 pm

Try the one in sig

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 2:18 pm

Ive tried what was shown in your change mtu all os's link, and its the same as it was. Actually it was already there as 1500??

Any other ideas?

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 3:39 pm

Ive ran a search through my registry and all settings that have the phrase "MTU" in them are already set to 1500, so unless I need to add a key somewhere, what else do I do to cure this??

MTU = 1465
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1425
Maximum useful data in each packet = 1425, which equals MSS.
MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 256960
RWIN Scaling (RFC1323) = 2 bits
Unscaled Receive Window = 64240
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
501600 (MSS x 44 * scale factor of 8)
250800 (MSS x 44 * scale factor of 4)
125400 (MSS x 44 * scale factor of 2)
62700 (MSS x 44)

bandwidth * delay product:
Your RcvWindow limits you to: 10278.4 kbps (1284.8 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4111.36 kbps (513.92 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 52 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000

mnosteele52 · Post by **mnosteele52** » Thu Aug 15, 2002 4:14 pm

Please read the Help & Tips link in my signature and try the suggested fix for improper MTUs.

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 6:03 pm

TCP options string = 020405910103030201010402

MTU = 1465
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.

MSS = 1425
Maximum useful data in each packet = 1425, which equals MSS.
MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 256960
RWIN Scaling (RFC1323) = 2 bits
Unscaled Receive Window = 64240
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
501600 (MSS x 44 * scale factor of 8)
250800 (MSS x 44 * scale factor of 4)
125400 (MSS x 44 * scale factor of 2)
62700 (MSS x 44)

bandwidth * delay product:
Your RcvWindow limits you to: 10278.4 kbps (1284.8 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4111.36 kbps (513.92 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 52 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000

Ill run down your fixes and explain..

AOLFIX - there is no NdisWan thread in that folder
DSLWinPoet - No iVasion Poet Adapter there
DSL Enternet - No MaxFrameSize thread

Your other fixes
1. Done
2. No IPMTU Key in that folder (default=0, Pramdesc, type)
3. Done
4. Done

You can see the results above

Anything else I can possibly try.. I downloaded both DRTCP and TCPOptimizer.. Both say 1500 is the MTU for my adapter?

What do i do!!??

rmrucker · Post by **rmrucker** » Thu Aug 15, 2002 6:11 pm

First off, don't worry. If your highest MTU is only 1465 -- this is not a huge deal. That is still 97.667% of 1500...

Second, there are multiple reasons why your MTU may be low -- and some of these are out of your control. Your ISP can limit your MTU and you will not be able to modify this.

1) Have you used the Optimizer to 'ping' your largest ping packet?
2) Are you on PPPoE -- if so, what client are you using? Have you tried using RASPPPoE?
3) Do you have ICS or VPN/IPSEC software that you are using?

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 6:27 pm

Originally posted by rmrucker
First off, don't worry. If your highest MTU is only 1465 -- this is not a huge deal. That is still 97.667% of 1500...

Second, there are multiple reasons why your MTU may be low -- and some of these are out of your control. Your ISP can limit your MTU and you will not be able to modify this.

1) Have you used the Optimizer to 'ping' your largest ping packet?
2) Are you on PPPoE -- if so, what client are you using? Have you tried using RASPPPoE?
3) Do you have ICS or VPN/IPSEC software that you are using?

Im not so much concerned about my MTU not being 1500, its the fact that the optimizers and all registry settings say 1500 and its still 1465.. Know what I mean? Im a Sys Admin so things that dont seem right make me wonder.

1. It becomes fragmented at 1476, but then shows 1465 and times out. Then shows "Couldn't determine largest possible MTU due to packets being lost. You might want to try a different URL". Ive tried multiple address.. same thing occures.

2. No PPPoE.

3. Im not using any ICS or VPN that I know of. Is there anyway to tell for sure?

Thanks.

joecool169 · Post by **joecool169** » Thu Aug 15, 2002 6:31 pm

ICS- Internet Connection Sharing will asign you an ip address in the private range like 192.168.0.xxx

VPN- Virtual Private Networking would show up in the networking control panel

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 6:42 pm

No ICS then.

MSVPN adapters show in the Network control panel

Microsoft VPN Adapter, click properties, bindings, there is a check mark next to NDISWAN->MSVPN Adapter

Then there is another connection that looks like:

NDISWAN-> MSVPNAdapter.. but its not configured.

?

MaStaMooN · Post by **MaStaMooN** » Thu Aug 15, 2002 8:27 pm

TTT,

dont abandon me!

rmrucker · Post by **rmrucker** » Thu Aug 15, 2002 9:12 pm

I am not sure why you have such packet loss with the ping test. Do you know how to ping in DOS? Can you use a Command Window to figure out what your maximum buffer size is?

The point here is we need to see if packet size is limited on multiple protocols (TCP and ICMP) or just TCP.

MaStaMooN · Post by **MaStaMooN** » Fri Aug 16, 2002 8:54 am

Ive seen on this site or another that there is a way to do the packet loss test directly from DOS.. I just cant remember the syntax on how to do it... Ill do a search, but anyone can jump in here at any time!

MaStaMooN · Post by **MaStaMooN** » Fri Aug 16, 2002 11:19 am

Using ping -l (packet size) site through DOS, I get the same results as doing it in the tweakers!

Anybody, Anybody, Bueller, Bueller....

rmrucker · Post by **rmrucker** » Fri Aug 16, 2002 1:32 pm

Are you using a router or hub or other device?

MaStaMooN · Post by **MaStaMooN** » Fri Aug 16, 2002 2:53 pm

My Connection to the Internet goes something like this:

My PC - Router- TSU/DSU - Router - T1 - Router - TSU/DSU - Router - Webserver - DSL Modem - Internet

Im guessing thats the connection.. Basically im in one location, the web server and modem are at another.. and we are connected by a full T1.

MaStaMooN · Post by **MaStaMooN** » Fri Aug 16, 2002 2:55 pm

Im actually getting decent speeds though.. bout 1250/350.. So im not complaining.. I just want to know why I cant change it.

rmrucker · Post by **rmrucker** » Fri Aug 16, 2002 9:05 pm

That's a lot of routers to go through! Any one of them could be limiting you. Can you ping the webserver with a full size packet (1472 buffer)? Can you ping anything else in that chain?? Perhpas you can locate the bottleneck that way...

MaStaMooN · Post by **MaStaMooN** » Fri Aug 16, 2002 9:41 pm

Would a Traceroute help you guys out with this?? Ill be back in the office on monday and give it a shot.

rmrucker · Post by **rmrucker** » Sat Aug 17, 2002 10:52 am

You could try to ping your own IP address and see if you can get a full size packet (-l 1472) to work. Then run a tracert and see how far a full size packet can go. If it does NOT even get as far as your IP address, then the limitation is in your computer.

MaStaMooN · Post by **MaStaMooN** » Tue Aug 20, 2002 8:59 am

Oh well.. I guess IM giving up on this as I have done just about everything in my power to figure this out.. All found registry hacks, updated drivers, pinging, tracerts, etc.. Just dont do the trick...

Guess ill have to live with the 1300/364 I am getting now. Luckly my company is moving in a few weeks and Ill have a full T1 to play with!! hehe

Thanks to all that offered help!

rmrucker · Post by **rmrucker** » Tue Aug 20, 2002 3:43 pm

If it is your NIC that is controlling the MTU, then getting a T1 line connected to the same NIC is going to give you the same MTU!

However, if it is a router that is controlling the MTU, then dumping the router will give you an MTU of 1500 whether or not you have the T1.

But, your speed is fine -- so I wouldn't worry about it!

MaStaMooN · Post by **MaStaMooN** » Tue Aug 20, 2002 3:56 pm

Ive done all I can with the PC, so Im hopeing that it is another part of the network holding me back. We will see in a month or so! heh

Thanks again,

natureguy007 · Post by **natureguy007** » Thu Aug 22, 2002 10:20 pm

except my mtu is 1462 ive tried pinging but it can ping past 1500 i must be doing something wrong i forgot how to becasue i did it before and only pinged to 1454 for data to be fragmented or something. i use nts enternet dun through pppoe and using a teryaon tj 615 cable modem through usb with semo.net and capped at 256k up and down speeds witch i get about 93 % of rated speed as my default rcv window is at 5688 with mss at 1422 can u help explain why my mtu is limited plus i dont think line coditions are much of a factor as im only 5000 feet or so from the servers and have brand new cable wireing in house. i have tried higher rwin but transfer efficency gets bad and retransmits to much.

natureguy007 · Post by **natureguy007** » Fri Aug 23, 2002 12:18 am

please reply you ignored this

rmrucker · Post by **rmrucker** » Fri Aug 23, 2002 10:49 am

Sorry, but a new IE Security Patch was released and it takes all of my time to investigate those!

Enternet keeps you from raising the MTU by setting a "MaxFrameSize". There are several techniques to fix that. I suggest starting your own thread and title it "How can I raise the Enternet MaxFrameSize" -- and you should get plenty of help.

SG Broadband Community

@ work, shared DSL connection, Win98se, MTU Problem

@ work, shared DSL connection, Win98se, MTU Problem

same problem

hello?