27 votes

How is possible that the web site is down but the traceroute is ok?

The website runs on a server process. When you shut down the server process, the server does not magically turn off. Also not when you misconfigure your firewall (and block port 80) neither does the ...
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  • 50.8k
14 votes
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Some visitors cannot access my website

If I'm not mistaken, the problem is that your registrar has published DS records for your domain - that is, DNSSEC signing keys: [me@risby player]$ dig ds ultreyatours.com [...] ;; ANSWER SECTION: ...
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  • 78.3k
10 votes

How is possible that the web site is down but the traceroute is ok?

Traceroute uses ICMP protocol to reach an address, and a HTTP server use HTTP protocol, different ports, and different approaches. I can reach an address via ICMP echo request but, if the port I'm ...
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9 votes
Accepted

Why am I getting different results from two servers that located in the same destination network?

You're leaving out a crucial piece of information, which is the subnet mask. You're making an incorrect assumption that these two hosts are in the same network/subnet based solely on the octet values ...
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  • 108k
8 votes

Why am I getting different results from two servers that located in the same destination network?

The same company host doesn't means that they are on the same network architecture... so route and ping might be different if they are connected to different network elements (proxy, firewall, ...
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  • 213
8 votes

Traceroute vs tracert

Windows' tracert is using ICMP while incrementing TTL to do probes: How to Use the TRACERT Utility The TRACERT diagnostic utility determines the route to a destination by sending Internet ...
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  • 8,702
5 votes

What does having * * * mean in the command traceroute ? and How can you cope with that situation?

It means that a packet with a tweaked TTL did not return an appropriate ICMP TTL exceeded packet, or that those packets were lost on the way back, within the given period traceroute waits for them. ...
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5 votes
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What does having * * * mean in the command traceroute ? and How can you cope with that situation?

It means that the affected host (in your example, the second one) did not reply to the traceroute. As by default traceroute uses an UDP port, you can change the discovery protocol to use ICMP/PING ...
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  • 43.6k
5 votes

Why am I getting different results from two servers that located in the same destination network?

Shorter answer: Thanks for providing the actual IP addresses. This helps us see what you are seeing to an extent. And here is what I am seeing. 37.211.166.178 appears to be unreachable while 37.211....
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  • 3,512
5 votes

Why am I getting different results from two servers that located in the same destination network?

If you are getting different traceroute results, it is because the routing is being handled differently. This could be because the hosts are not on the same network (as Paul's first comment under ...
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  • 337
5 votes
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How is possible that the web site is down but the traceroute is ok?

What Is a Virtual-Host? Some web-servers, like Apache, can be configured to use what's called virtual-hosting; essentially a local redirection service. In essence, it works like this: the web server(...
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5 votes
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why when i use tracert in powershell,it doesn't return complete reponse?

This does not look Powershell-related at all. Instead, it looks like your network (after 192.168.160.2) is filtering at least the ICMP Time exceeded responses, which is what tracert / traceroute ...
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  • 40.3k
5 votes

why Ethernet MTU size is 1500?

Setting an upper limit for packet size was done for two reasons: ensure reliable transmission of the data (longer data are more susceptible to being corrupted and their CRC have lower changes of ...
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  • 43.6k
5 votes
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how to test if aws nat gateway static ip is up?

One effective way to independently identify/confirm the source address you're using when going through a NAT device (gateway or instance) is by making an outbound request to a service on the Internet ...
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4 votes
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How does traceroute -T -p work?

Your results indicate changing routing. This has nothing to do with how traceroute operates. Please rerun your tests, and rerun them a second time if routing appears different. The no route to host,...
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  • 27.3k
4 votes

WHy is tracert working even though I changed my DNS settings to use a bad nameserver?

The answer to this question, as noted by @BrennenSmith, is that the DNS information is stored in the DNS cache file. As seen in the output of the nslookup command, the Non-authoritative answer ...
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  • 685
4 votes
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Where does tracert get its FQDN? And why can they differ?

Tracert uses GetNameInfoW internally, and as indicated in the "Remarks" section: The capability to perform reverse DNS lookups using the GetNameInfoW function is convenient, but such lookups are ...
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  • 6,257
3 votes

How to find the initial values of TTL for your current operating system?

Packets sent to localhost don't go over any hops so the ttl shown will be the starting value. Windows 10 C:\>ping -4 localhost Pinging Win10Main [127.0.0.1] with 32 bytes of data: Reply from ...
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  • 3,386
3 votes

View trace route through interface

No. Traceroute relies on ICMP Time Exceeded packets.
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  • 108k
3 votes
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Why a traceroute to a dynamic ip is different from static ip addresses?

An ISP that do network attribution change nothing, as each modem cable and such gear report to the ISP server upstream. Having a static IP just mean your router is not configured to ask an IP from a ...
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  • 16.2k
3 votes

Traceroute not returning result whereas ssh is working fine

traceroute or tracert in Windows is almost always the wrong tool to use to debug any kind of application, specifically the most known ones, like all based on TCP, with their default settings. This is ...
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3 votes
Accepted

Some IP addresses are unreachable due to invalid route

Your default Gateway is 192.168.0.1. So, if there is no Static route, the traffic will go over the default gateway, except for directly connected Networks. In your example above for 172.17.56.70, you ...
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  • 449
3 votes

Why does traceroute ended with additional hop after the destination?

traceroute works by sending UDP or ICMP Echo packets with sequentially increasing Time-to-Live (TTL) fields. TTL is decremented by 1 by each router that processes the packet. It expects two types of ...
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  • 344
3 votes
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How is the number of routers between source and destination known beforehand?

You are right in your original line of thinking. The number of hops is not known before hand and can indeed change. You are taking the quote a bit too literally, i.e incorrectly understanding that ...
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  • 316
2 votes
Accepted

Any protocol used by TRACEROUTE ? ICMP or UDP

This question has been addressed by Ladadadada here : Does traceroute use UDP or ICMP or both? The type of packet that is sent differs depending on the implementation. By default Windows tracert uses ...
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2 votes

Why woud ping fail but not traceroute

Most probably the pong from ping is blocked/gets discarded, while traceroute uses an error message form a node/hop to determine the route. Traceroute is not a standard tool, in that it uses a trick to ...
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2 votes

Why would tracert command in Windows timeout except for last hop?

Routers can be configured to not respond with an ICMP message that traceroute depends on. Also, MPLS can do that because it is not routing, it is label switching. When a router needs to create an ...
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  • 3,148
2 votes

Is there a utility or way to get the PMTU/MTU of a remote system quickly?

I found a solution after a lot of searching. Just going to link this here for anyone who cares: https://github.com/ValdikSS/p0f-mtu It has an API you can call with full socket support. So while ...
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2 votes

Bad destination address: foo.bar.local

The command from the question reveal that DNS is working and IP networking is working. What is wrong? :-) Your operating systems does not directly connect to the DNS like nslookup does. Name ...
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  • 3,044
2 votes
Accepted

Ping request timeout, followed by >10s times from laptop, but not from router

The ISP's modem/router itself was definitely doing something wonky. After some Googling I discovered that there was a root login on the router's web ui that allowed me to put it into "bridge mode." ...
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