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Martin Hope
Flint
Asked: 2015-03-25 14:16:41 +0800 CST
  • 0

It's been a while since I last touched squid and I've been sitting here figuring out this problem since the last few hours why my squid setup on this standalone server machine (behind router nat) failed to process any outgoing http requests from the machine itself and threw access denied messages on all the requests. I think I might have overlooked something obvious here but I can't spot it. Any idea what's wrong here?

% egrep -v "^\s*(#|$)" /etc/squid3/squid.conf
acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl localnet src fc00::/7       # RFC 4193 local private network range
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
acl SSL_ports port 443
acl Safe_ports port 80      # http
acl Safe_ports port 21      # ftp
acl Safe_ports port 443     # https
acl Safe_ports port 70      # gopher
acl Safe_ports port 210     # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280     # http-mgmt
acl Safe_ports port 488     # gss-http
acl Safe_ports port 591     # filemaker
acl Safe_ports port 777     # multiling http
acl CONNECT method CONNECT
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost manager
http_access deny manager
http_access allow localnet
http_access allow localhost
http_access deny all
http_port 3128 intercept
coredump_dir /var/spool/squid3
refresh_pattern ^ftp:       1440    20% 10080
refresh_pattern ^gopher:    1440    0%  1440
refresh_pattern -i (/cgi-bin/|\?) 0 0%  0
refresh_pattern (Release|Packages(.gz)*)$      0       20%     2880
refresh_pattern .       0   20% 4320


% sudo iptables -t nat -nvL  
Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 113 packets, 7598 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   25  1500 REDIRECT   tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:80 redir ports 3128

Chain POSTROUTING (policy ACCEPT 138 packets, 9098 bytes)
 pkts bytes target     prot opt in     out     source               destination         


% sudo sysctl net.ipv4.ip_forward  
net.ipv4.ip_forward = 1

% sudo tail -f /var/log/squid3/access.log
1427233173.711      1 192.168.0.3 TCP_MISS/403 4050 GET http://serverfault.com/favicon.ico - HIER_NONE/- text/html
1427233173.713      4 192.168.0.3 TCP_MISS/403 4130 GET http://serverfault.com/favicon.ico - HIER_DIRECT/190.93.247.183 text/html
1427233173.998      1 192.168.0.3 TCP_MISS/403 4082 GET http://serverfault.com/favicon.ico - HIER_NONE/- text/html
1427233174.000      5 192.168.0.3 TCP_MISS/403 4162 GET http://serverfault.com/favicon.ico - HIER_DIRECT/190.93.247.183 text/html
1427233189.293      1 192.168.0.3 TCP_MISS/403 4132 GET http://serverfault.com/ - HIER_NONE/- text/html
1427233189.295      5 192.168.0.3 TCP_MISS/403 4212 GET http://serverfault.com/ - HIER_DIRECT/190.93.246.183 text/html
linux
Martin Hope
Flint
Asked: 2013-09-06 20:58:02 +0800 CST
  • 1

Using output from the command below,

% curl -v stackoverflow.com/questions       
* About to connect() to stackoverflow.com port 80 (#0)
*   Trying 198.252.206.16...
* Connected to stackoverflow.com (198.252.206.16) port 80 (#0)
> GET /questions HTTP/1.1
> User-Agent: curl/7.29.0
> Host: stackoverflow.com
> Accept: */*

I could do curl -X GET -H "User-Agent: curl/7.29.0" -H "Host: stackoverflow.com" -H "Accept: */*" 198.252.206.16 to replicate the request but how do I specify the GET /questions in my command?

http
Martin Hope
Flint
Asked: 2012-07-03 06:47:23 +0800 CST
  • 6

I got this packet captured with tcpdump but I'm not sure how to use the --hex-string param to match the packet. Can someone show me how to do it?

11:18:26.614537 IP (tos 0x0, ttl 17, id 19245, offset 0, flags [DF], proto UDP (17), length 37)
    x.x.187.207.1234 > x.x.152.202.6543: [no cksum] UDP, length 9
        0x0000:  f46d 0425 b202 000a b853 22cc 0800 4500  .m.%.....S"...E.
        0x0010:  0025 4b2d 4000 1111 0442 5ebe bbcf 6701  .%[email protected]^...g.
        0x0020:  98ca 697d 6989 0011 0000 ffff ffff 5630  ..i}i.........V0
        0x0030:  3230 3300 0000 0000 0000 0000            203.........
tcpdump iptables packet
Martin Hope
Flint
Asked: 2012-01-01 22:59:47 +0800 CST
  • 18

I'm trying to convert an ini file into bash array variables. The sample ini is as below:

[foobar]
session=foo
path=/some/path

[barfoo]
session=bar
path=/some/path

so these become:

session[foobar]=foo
path[foobar]=/some/path
session[barfoo]=bar

and so on.

Right now, I could come up with only this command 

awk -F'=' '{ if ($1 ~ /^\[/) section=$1; else if ($1 !~ /^$/) print $1 section "=" $2 }'

Also, another problem is, it doesn't take spaces near = into consideration. I think sed is probably better suited for this job but I don't know how to hold and store a temporary variable for the section name in sed.

So any idea how to do this?

scripting bash configuration awk sed
Martin Hope
Flint
Asked: 2011-12-05 09:45:05 +0800 CST
  • 11

I'm operating a couple of server daemons that use udp to communicate with large number of clients. How do I find and list out all the active udp "connections" that are talking to the servers in order to estimate the num of active clients that are connected to the server daemons? I couldn't think of an easy way to do this besides sniffing the packets with tshark or tcpdump and look at the source ip of udp packets going to the server daemons and yes, I know UDP is connectionless and stateless protocol.

linux networking udp packet-analyzer