petrus's questions

Munin is quite verbose, and logs a bunch of things into munin-graph.log, munin-html.log, munin-limits.log and munin-update.log at each run of munin-cron.

I already reduced munin-node logging level by setting log_level 0 in munin-node.conf, and that works well. munin-node.log only gets updated when an error message is generated.

However I also tried to add the same option in munin.conf, but it makes munin crash.

How one can reduce the amount of logs written by munin?

I'm trying to tweak vsftpd to achieve maximum performance for my usage:

• I have only one or two clients that connect to the server.
• File size is between ~15MB and 1GB.
• Typical transfer batch represent between 1 and 2GB of data.

For testing purposes, I'm using a tmpfs on both sides (thus eliminating any disks bottleneck) with a single 1GB file.

When SSL is disabled, performance is good, with a transfer rate at ~120MB/s (reaching the limits of gigabit networking).

With SSL enabled only for control traffic (and not data traffic), performance drops at about 112MB/s, which is still within the acceptable limits.

However, when SSL is enabled for data flows, the transfer speed drops dramatically:

• 6.7MB/s using 3DES & SHA (ssl_ciphers=DES-CBC3-SHA in vsftpd.conf)
• 16MB/s using DES & SHA (ssl_ciphers=DES-CBC-SHA)

I didn't tested other ciphers, but from what I can see from the CPU usage during the transfer, it seems that vsftpd is only using a single cpu/core per client. While this can fit for large ftp sites with hundreds of clients, I'd like to avoid this behavior and use more ressources on the server.

On a side note, if you have any ideas regarding other openssl ciphers...

I have a vhost on my webserver whose sole and unique goal is to return the client IP adress:

petrus@bzn:~$ cat /home/vhosts/domain.org/index.php
<?php echo $_SERVER['REMOTE_ADDR']; echo "\n" ?>

This helps me troubleshoot networking issues, especially when NAT is involved. As such, I don't always have domain name resolution and this service needs to work even if queried by its IP address.

I'm using it this way:

petrus@hive:~$ echo "GET /" | nc 88.191.133.41 80
191.51.4.55

petrus@hive:~$ echo "GET /" | nc ydct.org 80
191.51.4.55

router#more http://88.191.133.41/index.php
88.191.124.254

However I found that it wasn't working from at least a computer:

petrus@seth:~$ echo "GET /" | nc ydct.org 80
petrus@seth:~$

petrus@seth:~$ echo "GET /" | nc 88.191.133.41 80
petrus@seth:~$

What I checked:

This is not related to ipv6:

petrus@seth:~$ echo "GET /" | nc -4 ydct.org 80
petrus@seth:~$ 

petrus@hive:~$ echo "GET /" | nc ydct.org 80
2a01:e35:ee8c:180:21c:77ff:fe30:9e36

netcat version is the same (except platform, i386 vs x64):

petrus@seth:~$ type nc
nc est haché (/bin/nc)
petrus@seth:~$ file /bin/nc
/bin/nc: symbolic link to `/etc/alternatives/nc'
petrus@seth:~$ ls -l /etc/alternatives/nc
lrwxrwxrwx 1 root root 15 2010-06-26 14:01 /etc/alternatives/nc -> /bin/nc.openbsd

petrus@hive:~$ type nc
nc est haché (/bin/nc)
petrus@hive:~$ file /bin/nc
/bin/nc: symbolic link to `/etc/alternatives/nc'
petrus@hive:~$ ls -l /etc/alternatives/nc
lrwxrwxrwx 1 root root 15 2011-05-26 01:23 /etc/alternatives/nc -> /bin/nc.openbsd

It works when used without the pipe:

petrus@seth:~$ nc ydct.org 80
GET /
2a01:e35:ee8c:180:221:85ff:fe96:e485

And the piping works at least with a test service (netcat listening on 1234/tcp and output to stdout)

petrus@bzn:~$ nc -l -p 1234
GET /
petrus@bzn:~$

petrus@seth:~$ echo "GET /" | nc ydct.org 1234
petrus@seth:~$

I don't know if this issue is more related to netcat or Apache, but I'd appreciate any pointers to troubleshoot this issue !

bzn is the server, hive is a working client and seth is the client on which I have the issue.

Edit: It works also with telnet but telnet doesn't allow piping.

2nd edit in answer to MickeyB:

Indeed host headers are not transmitted, but as seen with hive host above, I've configured the default vhost of Apache to behave like ydct.org vhost:

petrus@bzn:/etc/apache2/sites-available$ cat default
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName 88.191.133.41
        ServerAlias 2a01:e1b:1:132:1a0a:a9ff:fec8:f0a9
        DocumentRoot /home/vhosts/ydct.org/
</VirtualHost>

However, it works with curl!

petrus@seth:~$ curl ydct.org
2a01:e35:ee8c:180:221:85ff:fe96:e485

Output of apache2 -S posted to http://pastebin.com/aSf446Jv

But I'd like to know why it doesn't work with netcat...

My company recently deployed several Alcatel-based networks (7750SR) for ethernet and IP transport, and me and my team will have to support a part of it.

We're quite used to troubleshoot on Cisco and Juniper routers, but Alcatel-Lucent TiMOS is new to us and really different.

While we can have access to lab devices, I'd like to know if there is any emulator or simulator of ALU routers on which we can practice and test some configs.

I tried to search both on Internet and corporate intranet, but I don't even know what to look for...

I've been given two hpc cluster nodes, each with an infiniband hca.

Is it possible to connect them back-to-back, without using a switch ?