win98se cannot set mtu to 1500

spyghost · Post by **spyghost** » Sat Oct 25, 2003 10:41 am

hi,

i've followed all the instructions on this site on how to tweak the mtu settings for a dsl connection under a win98se os.

the problem now is that i speedguide cannot read my mtu as 1500. instead, it only shows 1454 as my mtu even though i placed 1500 in my MaxMTU.

is this a windows bug or what?

mccoffee · Post by **mccoffee** » Sat Oct 25, 2003 1:58 pm

My guess is ur on ppoe right ??

spyghost · Post by **spyghost** » Sat Oct 25, 2003 7:02 pm

yup, i use winpoet 6

mnosteele52 · Post by **mnosteele52** » Sat Oct 25, 2003 7:39 pm

Read here on how to fix your MTU.

spyghost · Post by **spyghost** » Sun Oct 26, 2003 10:34 am

great! that fixed the problem, but now, some sites do not display when mtu is set to 1500. is this another problem?

mnosteele52 · Post by **mnosteele52** » Sun Oct 26, 2003 10:55 am

Please post a current TCP/IP Analyzer test and tell us your ISPs caps.

mccoffee · Post by **mccoffee** » Sun Oct 26, 2003 12:17 pm

Your on ppoe you want ur mtu 1480 or 1492

mnosteele52 · Post by **mnosteele52** » Sun Oct 26, 2003 12:32 pm

Actually 1492 (he's using 98).

mccoffee · Post by **mccoffee** » Sun Oct 26, 2003 12:37 pm

I don't think it would do harm to use a 1480 mtu in 98 i could be wrong that should be a good test..

Andrzej · Post by **Andrzej** » Sun Oct 26, 2003 1:49 pm

w98 winpoet 6 dsl PPPoE - first result MTU=1454
after tweaking MTU=1500 but ... some sites do not display ...
so ... MTU value 1480 or 1492 ... hehehe

IMVHO simple - use router, the best PPPoE client
ask for recomendation

spyghost · Post by **spyghost** » Sun Oct 26, 2003 8:34 pm

TCP options string = 020405ac0103030201010402
MTU = 1492
MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1452
MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.
Default Receive Window (RWIN) = 255552
RWIN Scaling (RFC1323) = 2 bits (scale factor of 4)
Unscaled Receive Window = 63888

RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
127776 (MSS x 44 * scale factor of 2)
63888 (MSS x 44)
bandwidth * delay product:

Your RcvWindow limits you to: 10222.08 kbps (1277.76 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4088.832 kbps (511.104 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = OFF
Time to live left = 54 hops

TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349) = 00000000

if i set my mtu to 1500, some websites do not display and i cannot send e-mails.

mccoffee · Post by **mccoffee** » Sun Oct 26, 2003 9:46 pm

You want 1492 not 1500

mnosteele52 · Post by **mnosteele52** » Sun Oct 26, 2003 10:41 pm

OK now that your MTU is correct at 1492 let's optimize everything else. Please answer my question above........ what are your ISPs caps.

spyghost · Post by **spyghost** » Mon Oct 27, 2003 12:39 am

what are isp caps? i am really new to networking, dsl, and all those stuff...

i don't know if i have right stuff here, but...

os: win 98 se and win xp pro
isp: pldt mydsl (philippines)
advertised speed: 256

PLDT

mccoffee · Post by **mccoffee** » Mon Oct 27, 2003 12:46 am

Advertised speed is same as capps

spyghost · Post by **spyghost** » Mon Oct 27, 2003 12:52 am

ok, thanks... i got it right afterall...

so my caps is 256

mccoffee · Post by **mccoffee** » Mon Oct 27, 2003 1:26 am

Try the following in cablenut which is below me to download and install. .

DefaultReceiveWindow = 32768

DefaultSendWindow = 32768
DisableAddressSharing = 1
InitialLargeBufferCount = 200
InitialMediumBufferCount = 480
InitialSmallBufferCount = 640
LargeBufferSize = 81920
MaxFastTransmit = 64000
MediumBufferSize = 15040
PriorityBoost = 0
SmallBufferSize = 1280
TransmitWorker = 32
FastSendDatagramThreshold = 4096
EnableFastRouteLookup = 1
EnablePMTUDiscovery = 1
IgnorePushBitOnReceives = 0
GlobalMaxTcpWindowSize =17424
MaxFreeTcbs = 8000
MaxHashTableSize = 16384
MaxNormLookupMemory = 5000000
SackOpts = 1
SynAttackProtect = 1
Tcp1323Opts = 0
TcpLogLevel = 1
TcpMaxDupAcks = 3
TcpMaxHalfOpen = 100
TcpMaxHalfOpenRetried = 80
TcpRecvSegmentSize = 1452
TcpSendSegmentSize = 1452
TcpTimedWaitDelay = 30
TcpUseRFC1122UrgentPointer = 0
TcpWindowSize = 17424
MaxConnectionsPer1_0Server = 20
MaxConnectionsPerServer = 10
DefaultTTL = 64
DisableUserTOSSetting = 0
TcpMaxDataRetransmissions = 6
DefaultTOSValue = 92

spyghost · Post by **spyghost** » Mon Oct 27, 2003 2:01 am

i cant find some options

j79zlr · Post by **j79zlr** » Mon Oct 27, 2003 2:20 am

Try these, McCoffee gave you the XP/2000 settings:

BcastNameQueryCount = 1
BcastQueryTimeout = 100
BSDUrgent = 1
CacheTimeout = 600000
DefaultReceiveWindow = 17424
DefaultTTL = 64
EnableDNS = 0
GlobalMaxTcpWindoSize = 17424
KeepAliveInterval = 500
KeepAliveTime = 14000000
Lanabase = 0
LocalCopyMade = 1
MaxConnections = 100
MaxConnectRetries = 5
MaxDataRetries = 64
NameTableSize = 255
NameSrvQueryTimeout = 100
PMTUBlackHoleDetect = 0
PMTUDiscovery = 1
RoutingBufSize = 146432
RoutingPackets = 100
SackOpts = 1
SessionKeepAlive = 7200
SessionTableSize = 255
Size/Small/Medium/Large = 3
Tcp1323Opts = 0
TcpTimedWaitDelay = 30
MaxDupAttacks = 3
DefaultTOS = 240
IGPMLevel = 2
MaxConnectionsPer1_0Server = 10
MaxConnectionsPerServer = 8

mccoffee · Post by **mccoffee** » Mon Oct 27, 2003 3:30 am

98 DOH

spyghost · Post by **spyghost** » Mon Oct 27, 2003 5:09 am

i still can't surf and retrieve mails when mtu is 1500

mnosteele52 · Post by **mnosteele52** » Mon Oct 27, 2003 7:12 am

Originally posted by spyghost
i still can't surf and retrieve mails when mtu is 1500

Why are you setting it to 1500? It is supposed to be 1492.

spyghost · Post by **spyghost** » Mon Oct 27, 2003 9:29 am

is that so? why? others set it to 1500 and it works well

SICMF · Post by **SICMF** » Mon Oct 27, 2003 9:34 am

Originally posted by spyghost
is that so? why? others set it to 1500 and it works well

PPpOE MTU should be at 1492 not 1500.

j79zlr · Post by **j79zlr** » Mon Oct 27, 2003 9:36 am

RASPPPoE or most PPPoE clients use 8 bytes for authentication in the header of the TCP packet, since you are not allowing it that 8 bytes, you can't connect

XP's built in PPPoE client uses 20 bytes, so its MTU is 1480.

Cable or PPPoA does not send authentication information so it has an MTU of 1500.

hayc59 · Post by **hayc59** » Mon Oct 27, 2003 9:05 pm

Nice work guys!!

mnosteele52 · Post by **mnosteele52** » Tue Oct 28, 2003 2:36 am

spyghost please post a current TCP/IP Analyzer test.

spyghost · Post by **spyghost** » Tue Oct 28, 2003 9:08 am

ok,

i just did this a few seconds ago...

TCP options string = 020405ac0103030201010402
MTU = 1492
MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1452
MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.
Default Receive Window (RWIN) = 255552
RWIN Scaling (RFC1323) = 2 bits (scale factor of 4)
Unscaled Receive Window = 63888

RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
511104 (MSS x 44 * scale factor of 8)
127776 (MSS x 44 * scale factor of 2)
63888 (MSS x 44)
bandwidth * delay product:

Your RcvWindow limits you to: 10222.08 kbps (1277.76 KBytes/s) @ 200ms
Your RcvWindow limits you to: 4088.832 kbps (511.104 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 54 hops

TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349) = 00000000

i am using pldt mydsl professional, that is 256 kbps adsl pppoe

mnosteele52 · Post by **mnosteele52** » Tue Oct 28, 2003 9:11 am

Why have you even asked for help when you have ignored everything we told you?