Why can't i tracert from PC

AdrianH

AdrianH

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Flip, I feel dumb asking this, but for the life of me I can't tracert from PC. I can ping just fine, but tracert is a no go, and I don't know why.

Here's an example to WebAfrica

++++++++++++++
C:\Users\Adrian>tracert www.webafrica.co.za

Tracing route to www.webafrica.co.za [41.185.61.34]
over a maximum of 30 hops:

1 <1 ms 1 ms 1 ms 192.168.10.1
2 * * * Request timed out.
3 * * * Request timed out.
4 * * * Request timed out.
5 * * * Request timed out.
6 * * * Request timed out.
7 * * * Request timed out.
8 * * * Request timed out.
9 * * * Request timed out.
10 38 ms 37 ms 97 ms wnls-whmcs-web01.wadns.net [41.185.61.34]

Trace complete.
++++++++++++++

Anybody have any ideas?
 
I thought the 2nd hop would be to exchange. Does this mean that Telkom is now blocking the tracert responses?

Or does UnoTelly cause issues?
 
More likely your router is filtering out ICMP TTL exceeded replies.
 
AdrianH said:
I thought the 2nd hop would be to exchange. Does this mean that Telkom is now blocking the tracert responses?

Or does UnoTelly cause issues?
Click to expand...

Blocking is a strong word, the hardware maybe just setup to not respond to ping requests. Pretty standard practice.

Edit,

To anser you question, yes the 2nd hop should be the exchange, any reason you want to ping the exchange?
 
Scooby_Doo said:
Blocking is a strong word, the hardware maybe just setup to not respond to ping requests. Pretty standard practice.

Edit,

To anser you question, yes the 2nd hop should be the exchange, any reason you want to ping the exchange?
Click to expand...

It's nothing to do with not responding to ping requests.
 
AdrianH said:
I thought the 2nd hop would be to exchange. Does this mean that Telkom is now blocking the tracert responses?

Or does UnoTelly cause issues?
Click to expand...

Scooby_Doo said:
Blocking is a strong word, the hardware maybe just setup to not respond to ping requests. Pretty standard practice.

Edit,

To anser you question, yes the 2nd hop should be the exchange, any reason you want to ping the exchange?
Click to expand...

I just wanted to see if I had congestion. I got an sms from Telkom and Mweb late last week saying they are doing maintenance at the exchange, I then saw on Saturday afternoon i got a couple of disconnects, and subsequently a new port number.

So no, nothing pressing but I just like things to work.
 
AdrianH said:
I just wanted to see if I had congestion. I got an sms from Telkom and Mweb late last week saying they are doing maintenance at the exchange, I then saw on Saturday afternoon i got a couple of disconnects, and subsequently a new port number.

So no, nothing pressing but I just like things to work.
Click to expand...

If you have congestion pinging any IP address should show an increased latency number. No need to ping the exchange.
 
So what happens is your computer sends a request to the destination you specify. Either ICMP for a windows machine, or udp or tcp for a linux box.
Every packet sent has a TTL set. TTL is the number of hops a packet is allowed to traverse before "timing out" - if this mechanism didn't exist, then some packets could circle the internet forever!

When a router receives a packet it decrements the TTL before routing it. If the TTL is 0, the router sends an ICMP TTL Exceeded packet back to the source. Some devices are configured not to send these, which are the usual stars in a traceroute.
So your PC sends initially with a TTL of 1. So your first router sends the TTL exceeded back to you, and you see your first hop on the traceroute.
Your PC then sends with a TTL of 2 - it passes your first router, and the second one then receives a packet with TTL 1, and it sends back the ICMP TTL Exceeded packet.

That's how traceroute maps out the path to your destination.

For something like the OP is getting, their router/firewall is blocking out all the TTL Exceeded packets.
 
It could also be you are on one of the new ES VDSL nodes, although that should only be the 2nd hop. They don't respond to ICMP
 
Sinbad said:
More likely your router is filtering out ICMP TTL exceeded replies.
Click to expand...

I dont think he would receive the last reply then.

This is possibly something from your ISP.
I see people talking about pinging the exchange..
Your first layer 3 hope in most cases would be the BRAS device at your ISP (this is what responds to your PPPoe request)
 
Last edited:
syntax said:
I dont think he would receive the last reply then.

This is possibly something from your ISP.
I see people talking about pinging the exchange..
Your first layer 3 hope in most cases would be the BRAS device at your ISP that responds to the PPPoE request
Click to expand...

The last reply is an ICMP Echo Response. Different packet.
 
roadcat said:
It could also be you are on one of the new ES VDSL nodes, although that should only be the 2nd hop. They don't respond to ICMP
Click to expand...

There was maintenance on my exchange from Thursday last week, I got an SMS from both MWeb and Telkom saying I could experience on disruptions. I saw on Saturday afternoon I was disconnected and reconnected on a different port.

But the big question is, if my exchange was changed to a new ES VDSL nodes, what does this mean for me?
 
The problem has been solved. Turns out my PC firewall was blocking the ICMP for the trace routes. What I don't understand is why I must allow "incoming ICMP" on the firewall, surely the ICMP commands are outbound traffic.

bitdefender-firewall.png
 
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