Trivia question: max value for -w in ping command?

[MilesAhead]

Trivia question: max value for -w in ping command? I don't mean the max wait a ping can experience. I just mean the maximum value after -w on the command line that will not give an error. If they use a 32 bit integer then it's pretty big. But if it's only 16 bit maybe we're limited to 64k?

ping 127.0.0.1 -n 2 -w 50000 > nul
--------------------------^^^^


edit: I haven't found an answer on bing so I'm just curious if anyone knows.

edit2: for the purpose of this trivia let's limit it to W8 command line .. not Linux or OS/2 or whatever.

 

[Shadowjk]

I'm not entirely sure what the maximum is but what I believe you are trying to do is to set a wait period in a batch file?

For a wait out period I set the timeout period to 1000 (1 Second) and then use the count trigger to determine the amount of seconds to wait.

For example:

ping 127.0.0.1 -n 300 -w 1000 >nul

I set this command to wait 1 second between each ping and then repeat that 300 times. 300 Seconds = 5 minutes

Just a thought, I'll try and see if there is a maximum value...

EDIT: Just found out that the timeout switch will only come into effect if a ping destination is not reachable. Since a loopback address will always respond the timeout will not take effect. Try to ping a destination address that does not exist and it will. For example, sending a ping to 172.16.0.1 should fail since it is a private IP address and chances are that you will not have one on a home network. The timeout between each ping will then take affect. As a test I decided to try a timeout of a massive number and appears to be working so I am not entirely sure of the max value:



Now that I know this I am going to change some scripts I had to allow the 1 second timeout between each ping...

Josh

 

[MilesAhead]

I should have used the line from a post that made me ask this question instead of the localhost address
ping 192.0.2.2 -n 1 -w 60000 > nul

(the page example used only 6000 for six seconds per 'n' : I made it 60000)

According to the page where I found this line that address is supposedly defined as unreachable by standard.

I used such a high number of milliseconds because the user wanted a delay of minutes. I figured if I made the number after -n equal to minutes it would be easier to understand.

I'm just curious what the threshold of ms is. I suspect it's at least 32 bit signed integer but you never know with command line legacy code. I'm glad I searched on it because I was using ping for seconds delay with the 127 address too in my batches.

 

[Shadowjk]

192.0.2.2 would be a public IP address so someone may have it on the internet or it may not be used. I don't know...

I have decided to use an autoconfiguration address that is only used when a device cannot get a DHCP offer (169.254.xxx.xxx)

Either way, as long as it offers a timeout the parameters should be met

Josh

 

[MilesAhead]

Here's where I got the IP address:
scripting - How to wait in a batch script? - Stack Overflow

He quotes some RFC that guarantees it won't exist. All I know is I did nslookup and got "non existent domain"

 

[Shadowjk]

Hmmm... I didn't know that! Cheers for the link

 

[MilesAhead]

I didn't actually look at the RFC. I took his word for it.