Solstice Firewall Config

2007-12-25 9:46:00

Sorry for the late summary but I have yet to hear from Checkpoint so the

summary is sort of incomplete. I am putting the answers just after the

questions. Thanks to Hendrik Visage <Hendrik.Visage@VECTOR.CO.ZA> for

detailed response.

------------- ORIGINAL QUESTION WITH ANSWERS EMBEDDED ------------------------

Hello Managers, this question pertains to Netra/Firewall. I am depicting

below the diagram of our present n/w.[hiding all addresses, of course :)]

Internet

   |

Router0(Cisco) bbb.bbb.bbb.1

   |

   |

   |bbb.bbb.bbb.0 ccc.ccc.ccc.0

 __|____ ________

| TR 0 | | TR 1 |

 -------\ /--------\

         \0______1/ \

          Sun 625i \

                            Router1(Cisco) ccc.ccc.ccc.1

                              |

                          Local Net (TR)

                           has a client - xxx.xx.x.101(unregistered)

Router0 - aaa.aa.aa.aaa(serial), bbb.bbb.bbb.1 (Token Ring interface)

TR 0 - Token Ring 0 (bbb.bbb.bbb.0)

Sun's IP address at TR0 - bbb.bbb.bbb.11

Sun's IP address at TR1 - ccc.ccc.ccc.11

TR1 - Token Ring 1 (ccc.ccc.ccc.0)

Router1 - ccc.ccc.ccc.1

Client - xxx.xx.x.101 (unregistered)

Firewall rule base is simply :

Source Destination Services Action

localnet Any Any Accept

Any Any Any Reject

localnet's ip address is ccc.ccc.ccc.0

fwxlconf table has a entry:

>From To Method 1st Translated address

xxx.xx.x.21 xxx.xx.x.240 FWXT_SRC_STATIC bbb.bbb.bbb.21

There is no host on TR1 (We will be putting mail,ftp, etc. servers later

here) and all hosts are behind Router1.

netstat -rn gives :

Dest. Gateway

127.0.0.1 127.0.0.1

xxx.xx.0.0 ccc.ccc.ccc.1 <<-- Entered manually

bbb.bbb.bbb.0 bbb.bbb.bbb.11

ccc.ccc.ccc.0 ccc.ccc.ccc.11

default bbb.bbb.bbb.1

Now the questions AND ANSWERS are :

---------------------------------

Q1. The client does not work if we do not put 2nd entry manually. Our

understanding is that since translation table should translate client's

address to a registered address, this entry should not be there. Why does

Sun m/c needs this routing info ?

A1. Kernel is able to route only untranslated IPs so this is required.

Q2. We have plans to connect other internal (unregistered) networks too.

Does that mean we have to put their routing info also ?

A2. Yes

Q3. If answer to Q2 is yes, how can our network get connected to a host

outside whose registered address happens to be one of our internal addresses

? Firewall will never allow any packet to be received from that host because

of anti-spoofing.

A3. To use internal addresses mentioned in RFC 1597. These addresses are :

10.0.0.0 10.255.255.255

172.16.0.0 172.31.255.255

192.168.0.0 192.168.255.255

Unfortunately, not all of our internal addresses are falling in this range.

We are trying to find out a solution from Checkpoint.

Q4. What is the advantage/disadvantage of using FWXT_SRC_STATIC versus

FWXT_HIDE ? Does FWXT_HIDE gives only one (legal)IP address as compared to

FWXT_SRC_STATIC which provides a range ?

A4. FWXT_HIDE is useful when you have few or only one legal IP address. For

a session, it attaches a unique port# so it is a sort of dynamic. Nobody can

connect from outside.

FWXT_SRC_STATIC is used for range of addresses and for 2-way

communication(like mail server), it is used in conjunction with FWXT_DST_STATIC.

Q5. Can I have dynamic addressing translation instead of static ? FW

software gives only two options : FWXT_SRC_STATIC (with FWXT_DST_STATIC) and

FWXT_HIDE.

A5. FWXT_HIDE is dynamic.

Thanks

...manjeet

*******************

Manjeet Singh Rekhi

(manjeet@iglou.com)

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