TTL with ICMP

[netwalker1]

Dear All :
I have 3 PCs in my network :
PC1 , PC2 and PC3

PC1 --Ping-- PC2 --> TTL=128
PC1 --Ping-- PC3 --> TTL=253

why the TTL is different ?
why sometimes it gives me TTL=63 or any other number ?
is there anything from the destination ,

all the PCs are reachanble without any routers in-between !

Mohamed Farid
[green]Know Me No Pain , No Me Know Pain !!![/green]

 

[RookThis]

http://www.visualware.com/resources/tutorials/tracert.html

 

[mpennac]

Various operating systems use different starting time to live values. For example, early version of MS Windows used a TTL of 32. This was great when networks were small, but as the Internet grew so did the starting TTL. Most Windows systems start with a TTL of 128 these days. I have noticed that Windows 2003 server is now using a TTL of 64.

Here are the popular starting values; 32, 60, 64, 128, and 255. This value is decremented by 1 for each router it passes through. From your example, a value of 253 would indicate the frame has passed through 2 routers.

Hackers can use this information to try to identify the operating system at the far end of the connect.

Mike

http://www.nps-llc.com