The Official Unofficial Zorp FAQ (Frequently Asked Questions)

Magosányi Árpád

You can find here questions which are most frequently asked about zorp-gpl.

1. General questions

• 1.1 Why Zorp is better?
• 1.2 Isn't the Official Unofficial Zorp project a fork? Forks are frowned upon for good reasons.
• 1.3 What is the version policy?

2. Http related questions

• 2.1 How can I filter URIs in the http proxy?
• 2.2 How can I insert the address of the client into a header of the http request?
• 2.3 I have one IP addressable from the internet, but my DMZ contains more web servers. What can
• 2.4 A general HTTPS-browsing scenario
• 2.5 What about "HTTP 200 Document follows" ?
• 2.6 How can I configure the http proxy to handle ftp traffic?
• 2.7 How can I route https traffic arriving to my firewall to two
• 2.8 How can I handle windows update service?

3. Non-http related questions

• 3.1 What does stacking means?
• 3.2 What does stacking under and stacking sideways means?
• 3.3 How much memory is eaten by Zorp proxies?
• 3.4 Would like to get some more details about the performance of Zorp and connection setup rates.
• 3.5 How can I serve a huge number of concurrent threads with the smallest possible delay?
• 3.6 How can I redirect the session to an arbitrary destination?
• 3.7 How to define a zone with an irregular IP range?
• 3.8 The ftp proxy says: "Possibly bounce attack" what did happen?
• 3.9 Zorp bails out with no useable logs even when I bump up log level. What to do?
• 3.10 Does the gpl version of zorp offer any authenication? I want to auth against my openldap server.
• 3.11 How can I control protocols which Zorp does not have a proxy for?
• 3.12 How can I use bandwith_to_client and bandwith_to_server to control
• 3.13 Do you have an ssh proxy?

4. Iptables, tproxy, kernel, network setup

• 4.1 Can I use Zorp version 2.x with kernel version 2.2.x ?
• 4.2 What is this tproxy thing? Do I need it?
• 4.3 How to set up the dummy interface?
• 4.4 How to keep the port numbers with tproxy?
• 4.5 What is the difference between REDIRECT and TPROXY?
• 4.6 Does Zorp 2.x work with linux kernel 2.2.x?
• 4.7 How I figure out the original destination address in C?
• 4.8 Is there documentation anywhere for iptables.conf.in? There's no man-page or anything else I can find in Zorp GPL.
• 4.9 What is the difference between %d and %s in python formatted strings?
• 4.10 What is the right way to use a virtual ip address (alias) bound to an outside interface and forward traffic to a host in the private network?