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Hi, can someone take a look at the capture and let me know why so many dup acks and perhaps help me determine why my inside lan is so darn slow? this capture is a file transfer of malware bytes from my machine to my lan file server.

thank you

https://www.dropbox.com/s/rivkrj62a3g10a9/tmg%20file%20xfer.pcapng

asked 28 Aug '13, 10:10

netnerd's gravatar image

netnerd
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accept rate: 0%


You PC is configured with an MTU size of 1300 bytes, resulting in an MSS of 1260 bytes only. So this would be the first thing to check.

The majority of lost packets is reported by the LAN Server running in VMWare at 192.168.179.6. Given that this is a flat network I'd guess these packets are dropped in the VMWare environment.

MTU size and the optimum mtu size for my laptop is 1300. pinging with mtu size of 1272 does not fragment

That is certainly not the optimum for a flat Ethernet network but obviously it is configured.

netsh interface ipv4 show subinterfaces

will show the actual settings and

netsh interface ipv4 set subinterface "1" mtu = 1500 store = persistent

could be used to bump this up to the standard ethernet MTU size.

As for the packet drops in VMware I suggest you google on "vmware packet drops" and/or address this issue to a better suitable forum.

permanent link

answered 29 Aug '13, 04:21

mrEEde's gravatar image

mrEEde
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accept rate: 20%

edited 29 Aug '13, 12:41

Thanks for your input. So do I need to look at the vmware environment, and what would you suggest for improving the performance? I checked my MTU size and the optimum mtu size for my laptop is 1300. pinging with mtu size of 1272 does not fragment, and then I add 28 for the 20bytes of iP header and 8 bytes of icmp echo header. So adjusting my mtu on my nic is not really necessary according to what I've been reading. Thanks for looking at this.

(29 Aug '13, 09:43) netnerd
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question asked: 28 Aug '13, 10:10

question was seen: 1,707 times

last updated: 29 Aug '13, 12:41

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