change timeout for dropped ip traffic

Question

I am behind a corporate firewall, which simply drops (swallows) all ip-traffic to unknown ip-addresses.

It takes a lot of time for Linux (Ubuntu 13.10) to abort my erroneous connection-attempts, causing quite a few applications to hang.

Which setting do I have to change to get shorter timeouts for dropped connection attempts? I assume this is done in in /proc/sys/net/ipv4?

I am using IP4. To give an indication about the current timeout I tried

$ time wget -t1 212.123.12.153
--2014-03-14 12:40:42--  http://212.123.12.153/
Connecting to 212.123.12.153:80... failed: 

Giving up.


real    2m8.637s
user    0m0.003s
sys     0m0.003s

I guess they won't change the firewall to reject traffic instead of drop it? — Halfgaar, Mar 14 '14 at 12:28
It is a big company. I think changing a setting in linux is the easier way to do this. — mirk, Mar 14 '14 at 13:24

score 0 · Answer 1 · answered Mar 14 '14 at 15:22

0

Dropping the number of retries from the default 6 to 1 does the trick. This method has obvious drawbacks though.

The parameter can be set with the command below, run as superuser.

echo 1 >  /proc/sys/net/ipv4/tcp_syn_retries

answered Mar 14 '14 at 15:22

mirk

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change timeout for dropped ip traffic

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