| 1 |
Kashani wrote: |
| 2 |
|
| 3 |
> I've been Googling for a few hours looking for information from |
| 4 |
>anyone actually using syn cookies in a production system. We'd been hit |
| 5 |
>with a few syn floods recently and were looking at a number of ways to |
| 6 |
>stop them. |
| 7 |
> |
| 8 |
> From my research it appears that syn cookies should not affect the |
| 9 |
>TCP session. There are some references to syn cookies causing slow downs |
| 10 |
>with SMTP and ftp, but nothing really concrete. Also most of the info is |
| 11 |
>from 2001 when 2.4 came out and syn cookies were linked with the newer |
| 12 |
>iptables code. Was looking for case studies and hard stats. |
| 13 |
> |
| 14 |
> I'd like to hear from anyone running web server farms that has syn |
| 15 |
>cookies turned on. Ideally you'd be pushing a fair amount of traffic or |
| 16 |
>have 1k concurrent users per server at some point so I know it'll scale. |
| 17 |
>Did you have any problems, weird firewalls blocking your servers, latency |
| 18 |
>connection to the server, load balancers didn't like it, weird connections |
| 19 |
>that hung around forever, and so forth. |
| 20 |
> |
| 21 |
>Thanks in advance, |
| 22 |
>kashani |
| 23 |
> |
| 24 |
> |
| 25 |
The only thing syn cookie will affect is the sistem itself and its |
| 26 |
responsiveness to connections/sessions... |
| 27 |
not other network equipment.. If i'm not missing something.. |
| 28 |
|
| 29 |
to the outside world, there is no diference, unless, accepting "known" |
| 30 |
connections faster than unknown ones... |
| 31 |
Latency connection should drop, since that is the purpose of syn cookies |
| 32 |
(enhance performance on very high network connections, or DoSs) |
| 33 |
about the load balancer... shouldn't have problems..since I never used |
| 34 |
one... can only reason theoretically on this.. |
| 35 |
weird connections that would hung forever would seem like, syn cookie |
| 36 |
support bug... |
| 37 |
|
| 38 |
compliments, |
| 39 |
|
| 40 |
-- |
| 41 |
|
| 42 |
Miguel Figueiredo Mascarenhas de Sousa Filipe |
| 43 |
email: miguel@×××××××××××.pt (PORTUGAL) |
| 44 |
http://mega.ist.utl.pt/~miguel |
| 45 |
|
| 46 |
Equipa de Administração de Sistemas |
| 47 |
Rede das Novas Licenciaturas (RNL) |
| 48 |
Instituto Superior Técnico |
| 49 |
http://www.rnl.ist.utl.pt |
| 50 |
http://mega.ist.utl.pt |
Archives