topic Re: Not able to open web page in Routing and SD-WAN

Not able to open web page

Debabrata Majhi — Fri, 03 May 2019 14:45:03 GMT

Hi All

Can any one help me to solve the below mentioned issue.Actual in X.20 .one web service is running but page is not opening when i am trying to open by any browser

We can telnet by port 80 and also IP address is proper ping and trace route

Do you thing is their any routing issue?

Can you help to troubleshoot

No.	Time	Source	Destination	Protocol	Length	Info
1	8.32845	X.X.X.248	X.X.X.20	TCP	62	58369 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
2	8.328711	X.X.X.248	X.X.X.20	TCP	62	58370 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
3	8.579086	X.X.X.248	X.X.X.20	TCP	62	58371 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
4	11.328614	X.X.X.248	X.X.X.20	TCP	62	[TCP Retransmission] 58370 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
5	11.332618	X.X.X.248	X.X.X.20	TCP	62	[TCP Retransmission] 58369 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
6	11.582588	X.X.X.248	X.X.X.20	TCP	62	[TCP Retransmission] 58371 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
7	17.324976	X.X.X.248	X.X.X.20	TCP	58	[TCP Retransmission] 58369 > 80 [SYN] Seq=0 Win=8192 Len=0 SACK_PERM=1
8	17.331914	X.X.X.248	X.X.X.20	TCP	58	[TCP Retransmission] 58370 > 80 [SYN] Seq=0 Win=8192 Len=0 SACK_PERM=1
9	17.575977	X.X.X.248	X.X.X.20	TCP	58	[TCP Retransmission] 58371 > 80 [SYN] Seq=0 Win=8192 Len=0 SACK_PERM=1
10	21.888232	X.X.X.248	X.X.X.20	ICMP	74	Echo (ping) request id=0x0008, seq=28705/8560, ttl=128 (no response found!)
11	26.683915	X.X.X.248	X.X.X.20	ICMP	74	Echo (ping) request id=0x0008, seq=28727/14192, ttl=128 (no response found!)
12	30.005386	X.X.X.248	X.X.X.20	TCP	62	58399 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
13	30.005653	X.X.X.248	X.X.X.20	TCP	62	58400 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
14	30.258942	X.X.X.248	X.X.X.20	TCP	62	58401 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
15	31.685366	X.X.X.248	X.X.X.20	ICMP	74	Echo (ping) request id=0x0008, seq=28749/19824, ttl=128 (no response found!)
16	33.006871	X.X.X.248	X.X.X.20	TCP	62	[TCP Retransmission] 58400 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
17	33.006906	X.X.X.248	X.X.X.20	TCP	62	[TCP Retransmission] 58399 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
18	33.25982	X.X.X.248	X.X.X.20	TCP	62	[TCP Retransmission] 58401 > 80 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 WS=256 SACK_PERM=1
19	36.687823	X.X.X.248	X.X.X.20	ICMP	74	Echo (ping) request id=0x0008, seq=28771/25456, ttl=128 (no response found!)
20	39.009208	X.X.X.248	X.X.X.20	TCP	58	[TCP Retransmission] 58400 > 80 [SYN] Seq=0 Win=8192 Len=0 SACK_PERM=1
21	39.009247	X.X.X.248	X.X.X.20	TCP	58	[TCP Retransmission] 58399 > 80 [SYN] Seq=0 Win=8192 Len=0 SACK_PERM=1
22	39.030974	X.X.X.20	X.X.X.248	TCP	62	80 > 58399 [SYN, ACK] Seq=0 Ack=1 Win=4380 Len=0 MSS=1380 SACK_PERM=1
23	39.03114	X.X.X.248	X.X.X.20	TCP	54	58399 > 80 [ACK] Seq=1 Ack=1 Win=65392 Len=0
24	39.032189	X.X.X.248	X.X.X.20	HTTP	529	GET /logon.htm HTTP/1.1
25	39.238861	X.X.X.20	X.X.X.248	TCP	60	80 > 58399 [ACK] Seq=1 Ack=476 Win=3905 Len=0
26	39.250968	X.X.X.20	X.X.X.248	TCP	231	80 > 58399 [PSH, ACK] Seq=1 Ack=476 Win=3905 Len=177 [TCP segment of a reassembled PDU]
27	39.263194	X.X.X.248	X.X.X.20	TCP	58	[TCP Retransmission] 58401 > 80 [SYN] Seq=0 Win=8192 Len=0 SACK_PERM=1

Re: Not able to open web page

balaji.bandi — Fri, 03 May 2019 16:00:57 GMT

what is the error you getting when you browse http://x.x.x20/

is this web server Linux or IISe ?

Re: Not able to open web page

Sebastian Fernandez — Sat, 04 May 2019 00:42:35 GMT

Use TCP MSS 1380 and also try to clear DF bit if your application is setting one. There are ECN and re-transmissions happening which leads me to think of the two. Also if you are able to open the telnet port but not able to access via http, I wonder if there is some application issue.

Is your web server accessible on the remote network itself via http.

Re: Not able to open web page

Debabrata Majhi — Sat, 04 May 2019 05:00:04 GMT

Hi BB

Thanks for your response.

It is a device ,through which will get some environment health

Re: Not able to open web page

Debabrata Majhi — Sat, 04 May 2019 05:12:55 GMT

TCP MSS 1380-Where I will configure it ,Like in Switch port where it is directly connected.I am able to open the http page by locally(direct p2p).But remotely it is not accessible via browser(But ping and telnet via port 80 accessible) .

Can you please share the command also

Thanks

Debu

Re: Not able to open web page

Georg Pauwen — Sat, 04 May 2019 07:12:22 GMT

Hello,

what do you mean by being able to open the web page locally ? Is this web page hosted in your own network ? And remote access means access from the public Internet ?

MTU and MSS values would normally be configured on the outgoing interface (the one with a public IP address), e.g.:

interface Dialer1

description ISP Link

mtu 1492

ip tcp adjust-mss 1452

Re: Not able to open web page

Debabrata Majhi — Sat, 04 May 2019 13:06:57 GMT

locally means-Lets say It is installed in site-A-This is a device by which will get some input for this device to check the device health.When my laptop and device is directly connected via LAN cable.I am able to access the web page.

But when I am in central office (Central office and Site-1 is connected via MPLS) and trying to get access the web page ,It is not opening

But at the same time able to do ping as well telnet via port 80.

Hope I able to make you understand

Please suggest some troubleshooting steps.

Re: Not able to open web page

Georg Pauwen — Sat, 04 May 2019 16:54:21 GMT

Ping the IP address of the website with different packet sizes until you the message 'Packet needs to be fragmented but DF set' message. At what packet size do you get that ?

C:\Users\pauwe>ping -l 1400 -f www.google.com

Pinging www.google.com [172.217.17.68] with 1400 bytes of data:
Reply from 172.217.17.68: bytes=64 (sent 1400) time=12ms TTL=54
Reply from 172.217.17.68: bytes=64 (sent 1400) time=120ms TTL=54
Reply from 172.217.17.68: bytes=64 (sent 1400) time=55ms TTL=54
Reply from 172.217.17.68: bytes=64 (sent 1400) time=115ms TTL=54

Ping statistics for 172.217.17.68:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 12ms, Maximum = 120ms, Average = 75ms

C:\Users\pauwe>ping -l 1480 -f www.google.com

Pinging www.google.com [172.217.17.68] with 1480 bytes of data:
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

Ping statistics for 172.217.17.68:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

Re: Not able to open web page

Debabrata Majhi — Tue, 07 May 2019 10:33:11 GMT

Hi Georg Pauwen

I think we are in right direction

Their is other device which we are getting response

ping -l 1450 -f X.X.X.20==Getting reply

Faulty device

ping -l 1450 -f X.X.X.21==Getting Request timed out

Packet needs to be fragmented but DF set.

Now tell me the next action for the faulty device

Re: Not able to open web page

Georg Pauwen — Tue, 07 May 2019 11:22:26 GMT

Hello,

assuming that the 'faulty' device is a Windows machine, you can follow the procedure below. First, you obviously need to find out at what MTU size you get a proper response, and replace the value marked in bold with the one you have come up with:

1. Go to 'Run' and type 'cmd' to open a command prompt

2. Type “netsh interface ipv4 show subinterface”.
--> You will see a list of network interfaces.
3. Type “netsh interface ipv4 set subinterface `Local Area Connection` mtu=1472 store=persistent”.
You should replace Local Area Connection with the name that appeared in the “Interface” column from steps 1-3.
4. Press Enter.
5. Type “netsh interface ipv4 show subinterface” to check the result.

Re: Not able to open web page

Debabrata Majhi — Wed, 08 May 2019 13:02:11 GMT

Sorry for late response

The web service is hosted in a device(Not aware is windows or no).

I am using windows system.Do I need to change my system's LAN interface MTU ?

Awaiting for resonse for changes

Thanks