blocking user agents via IPTables?

[Original Poster]

hello all,

 

I was wondering if anyone new the best way to let through only specific user agents connect?

 

(I am aware people can change their user agents, but that is irrelevant to me at the moment)

 

any help would be great :)

 

thanks.

[+BudMan MVC]

What proxy are you using. I don't see how you could do with that sort of thing without a proxy, or layer 7 type of firewall. So what are you using to filter/block? Or is this on your server and your wanting to block specific useragents from accessing your service/httpd?

[dragon2611]

You need Layer 7 support 

 

http://l7-filter.sourceforge.net/ might help with that.

 

If I remember rightly it uses REGEX to match which is a bit of pain to get right (Well that could just be I'm not very good at writing regex patterns)

[Original Poster]

  On 05/08/2014 at 13:54, BudMan said:

What proxy are you using. I don't see how you could do with that sort of thing without a proxy, or layer 7 type of firewall. So what are you using to filter/block? Or is this on your server and your wanting to block specific useragents from accessing your service/httpd?

correct this is my proxy server (squid), but everyone is going via the server to access the internet so there is a linux machine between the clients and the interwebs so I was going to use IP tables to block everything but (lets say safari) if they are not using safari not forwarding to the interwebs

 

to summarise to clear up confusion

 

user -> server (IPtables->squid) -> internet

[+BudMan MVC]

in squid its simple acl that matches the UA you want to allow, and deny all others.

acl aclname browser [-i] regexp ...

# pattern match on User-Agent header (see also req_header below) [fast]

acl aclname req_header header-name [-i] any\.regex\.here

# regex match against any of the known request headers. May be

# thought of as a superset of "browser", "referer" and "mime-type"

# ACL [fast]

[Original Poster]

  On 05/08/2014 at 14:40, BudMan said:

in squid its simple acl that matches the UA you want to allow, and deny all others.

acl aclname browser [-i] regexp ...

# pattern match on User-Agent header (see also req_header below) [fast]

acl aclname req_header header-name [-i] any\.regex\.here

# regex match against any of the known request headers. May be

# thought of as a superset of "browser", "referer" and "mime-type"

# ACL [fast]

ok I will do it this way then thanks :) was actually just trying it out but I cannot seem to get it working... do you have an example (e.g.... MSIE?) or a useful link?

[+BudMan MVC]

do google for blocking browser useragent squid and you should find a couple of walk thru's - you are running what version of squid? I recall a previous thread with you about squid and you were running really old version - but I think you updated?

[Original Poster]

  On 05/08/2014 at 15:23, BudMan said:

do google for blocking browser useragent squid and you should find a couple of walk thru's - you are running what version of squid? I recall a previous thread with you about squid and you were running really old version - but I think you updated?

*cough* I am still using squid 2.4 :D I have latest squid 3 on the system from the other thread but for now this one is using 2.4. I will most likely upgrade after I have the browsers blocked

[+BudMan MVC]

Well 2.4 doesn't have the acls - believe they were added in 2.6, so like that last thread would explain why not working. At a loss to why anyone would be using such an old version?? 2.4 is like 2002 ;)

[Original Poster]

  On 05/08/2014 at 15:37, BudMan said:

Well 2.4 doesn't have the acls - believe they were added in 2.6, so like that last thread would explain why not working. At a loss to why anyone would be using such an old version?? 2.4 is like 2002 ;)

ah I meant i am using 2.7!? :p I am using the acls for blocking sites, but I cannot seem to get the blocking of browsers, just donot think I know enough about squid to block them/get it working http://gaugusch.at/squid.shtml i tried this guide but seemed to cause me issues

[+BudMan MVC]

Well that should work then.. But still why not using current 3.4? At a loss why anyone - especially in security area type software would use outdated versions, I can see being a version behind or so.. But 2.7 was released in 2008, and last change I see to that branch was 2011

[Original Poster]

  On 05/08/2014 at 15:45, BudMan said:

Well that should work then.. But still why not using current 3.4? At a loss why anyone - especially in security area type software would use outdated versions, I can see being a version behind or so.. But 2.7 was released in 2008, and last change I see to that branch was 2011

 

I will be upgrading, very shortly once i work out exactly what I need to do, I do not want to upgrade half way through experimenting for it not to work and me be confused as to why once I have finished this task and have the my prototype setup I will upgrade and will only use squid3 from then on (I also used squid 2.7 caching as squid3 cache refused to work if you remember from my previous post, and I could not seem to solve it) either way! im going to have to keep trying this out

[Original Poster]

  On 05/08/2014 at 15:45, BudMan said:

Well that should work then.. But still why not using current 3.4? At a loss why anyone - especially in security area type software would use outdated versions, I can see being a version behind or so.. But 2.7 was released in 2008, and last change I see to that branch was 2011

got it working! (upgrading tomorrow)

[+BudMan MVC]

so what were you doing wrong for the next guy that might have same sort of issue?

[Original Poster]

  On 05/08/2014 at 16:39, BudMan said:

so what were you doing wrong for the next guy that might have same sort of issue?

ah good point probably should say, thank you for reminding me.

 

the httpd_accel comman in the guide was not liked by squid in a very much shortened version of his guide assuming you can connect via the proxy just put this in under acl CONNECT method CONNECT line tested on an older MSIE version and it 403 errored tried it on chrome worked fine

 

acl CONNECT method CONNECT

acl ie_browser browser ^Mozilla/4\.0 .compatible; MSIE 

acl bad_browser browser ^Gator

http_access deny bad_browser

http_access deny ie_browser

http_access allow manager localhost #you will have this bold config already in place do not copy this over your working config

http_access deny manager

http_access deny !Safe_ports

http_access deny CONNECT !SSL_ports

http_access deny to_localhost

http_access allow localhost

http_access deny all

http_reply_access allow all

icp_access allow all

cache_mgr hostmaster@mycompany.at

append_domain .mycompany.at

deny_info ERR_IEBROWSER ie_browser

wccp_router 172.16.0.1

ie_refresh on

[+BudMan MVC]

you found that from this guide ;) http://gaugusch.at/squid.shtml did you not? That is from like 2006, so would assume some issues with it in 2014 ;)