I actually posted this question yesterday. I'm here to ask you guys again after testing.

↓↓↓First of all, please see my question↓↓↓

My customers told me that the access speed is really slow markedly!

[Circumstances] Everything is OK, every packet flows well. However, now I have focused on the speed... That is, connection is ok

[Issues] Whenever I connect or access the web servers, the access speed markedly slow. (It took for 10~20 seconds until web page has completed.)

However, it is fast sometimes... That is, slow, fast, slow, fast --- continuous

[The data] First, please see the below network structure. enter image description here [The things that I want to know] As you can see the data, the structure is not complicated. To tell the truth, I don't know what device is the problem. and I also don't know what can I see in order to fix it?

I just want to know whether device's problem. If so, how can I control it.

Regards, SK

I'll let you know how I test after posting this question yesterday. ( [L4, F/W]How can I deal with SPEED? ) <-- Yesterday question I posted.

  • I captured packets with wireshark. As you can see the below capture, it showed Retransmission message. However, the frequency was very low.

I assume that it is common situation that only one retransmission is showed.

enter image description here

For me, the speed is extremely normal. But my two customers among them told its speed was really low...


  • You know, on the google chrome, we can measure speed using F12 button. my customer captured this picture. (DNS lookup issue..?) enter image description here

What should I do..? I really want to get an advice..! Could you give me an advice? Regards, SK

  • Do you have control over your customers' networks? Are they connecting to you over the Internet? – Ron Maupin Jan 28 '16 at 6:44
  • My network. But my customer told connection was slow. and this customer's customer also told connection was slow.. If just one person said it's low, I understand that person's network is the problem. But another person also told it was slow.. Also, they connect it using smartphone tethering. (smartphone tethering is another network domain, isn't it? -> they told it "also" slow...) So.. how can I deal with it.. crazy...ㅠ_ㅠ (of course I tested it using 10 network domains). Please give an advice. – SK.Kwon Jan 28 '16 at 7:37
  • Your customer is on your network, or does your customer have a different network which is directly attached to yours? – Ron Maupin Jan 28 '16 at 7:49
  • My customer network is definitely different from my network. ... – SK.Kwon Jan 28 '16 at 8:07
  • And do you have control over that network and any networks in between? – Ron Maupin Jan 28 '16 at 8:09

To find the problem you must first know what the problem is. "Slow" is a horrible description, we don't know what it is being compared to. Do your own testing from different network segments, monitor utilization of the significant links and look for trends or a pattern of fast vs. slow. Easiest is to rule out network VS server. Check utilization, errors on the switch ports, etc. A speed/duplex mismatch anywhere could cause it. If you find nothing, then you will start looking into the servers' utilization. If there are multiple servers responding in a HA environment, maybe the responses are different from each. There are so many different possibilities right now, you need to narrow down the playing field until you get closer and closer.

  • One more point, try to utilize NSLOOKUP to confirm the speeds of the DNS responses. – Rylan Jan 28 '16 at 17:25
  • Thank you Rylan. Following your good suggestions, I'll give it a try ! One more question Rylan. As you can easily see the network structure that I questioned upper, IDC L2 switch is only 10/100 switch. Maybe can it be a part of problem???? – SK.Kwon Jan 29 '16 at 2:12

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