Levels of security and access lists

Similar Questions

• Levels of security ASA Firewall interface and access lists

  Hello

  I am trying to understand the correlation between the ACL and the levels of security on an ASA of the interface.

  I work with an ASA using both! ??

  Is this possible?

  Assumptions: Any ACL applied below is on the wire of transmission (interface) only in the inbound direction.

  Scenario 1

  interface level high security to security level low interface.

  No ACLs = passes as I hope

  What happens if there is an ACL refusing a test package in the above scenario?

  Scenario 2

  Low security to high

  No traffic = ACL will not pass as I hope

  What happens if there is an ACL that allows the trial above package.

  I have trawled through documentation on the web site and cannot find examples, including the two (using ACL in conjunction with security levels).

  Thank you in advance for any help offered.

  Levels of security on the interfaces on the SAA are to define how much you agree with the traffic from this interface.  Level 100 is the most reliable and 0 is least reliable.  Some people will use a DMZ 50 because trust you him so of internet traffic, but less traffic then internal.

  That's how I look at the levels of security:

  A security level of 1 to 99 always two implicit ACL.  To allow traffic down interfaces of security and the right to refuse traffic toward higher level security interfaces.  100 has a security level IP implicitly allowed a full and level 0 has implicit deny ip any one.

  In scenario 1, if you apply an ACL to deny a security level of 1-99, it will eliminate implicit permit than an entire intellectual property and deny traffic based on the ACL and all traffic.  You create an ACL to allow some other desired traffic.  If this ACL is applied to a security level of 100, he'll refuse essentially all traffic because it will remove the authorization implicit ip any any ACL.  Once again, you will need to create an another ACL to allow traffic.

  In scenario 2, if you apply a permit ACL to an interface of level 0 of security, it will allow that traffic, but continue to deny all other traffic.  However, if the security level is 1-100, it will be all traffic to that destination and remove the implicit ACL (permit and deny)

• PIX 535 and access lists

  Hello

  We have a Cisco PIX 535. By default, traffic on one more secure interface with a lower security level is allowed, what is?

  OK, I have a doubt, I had to define an access list entry to allow a telnet connection between inside and outside. There is no rule against that traffic, but without this rule the telnet connection cannot be established.

  And my question is: why? It is not supposed to be allowed by default?

  Thanks in advance.

  Higher default-> bottom is allowed... However, once you add instructions permit, it is implicitly deny all at the end. So, if you allow ftp and ssl web... so by default, any other traffic is denied and you need to be precise with your permit.

• IOS VPN on 7200 12.3.1 and access-list problem

  I'm in IOS 12.3 (1) a 7200 and have configured it for VPN access. I use the Cisco VPN client. Wonder if someone has encountered the following problem, and if there is a fix.

  The external interface has the access-list standard applied that blocks incoming traffic. One of the rules is to block the IPs private, not routable, such as the 10.0.0.0 concern, for example.

  When I set my VPN connection, none of my packets get routed and I noticed that outside access list interface blocks the traffic. When I connect to the router through VPN, the router attributes to the client an IP address from a pool of the VPN as 10.1.1.0/24. But normal outside the access list denies this traffic as it should. But as soon as I have established a VPN connect, it seems that my encrypted VPN traffic must ignore the external interface access list.

  If I change my external access list to allow traffic from source address 10.1.1.0/24 my VPN traffic goes through correctly, but this goes against the application to have an outdoor access list that denies such traffic and have a VPN.

  Anyone else seen this problem or can recommend a software patch or version of IOS which works correctly?

  Thank you

  R

  That's how IOS has always worked, no way around it.

  The reasoning is to do with the internal routing on the router. Basically an encrypted packet inherits from the interface and initially past control of ACL as an encrypted packet. Then expelled the crypto engine and decrypted, so we now have this sitting pouch in the cryptographic engine part of the router. What do we with her now, keeping in mind users may want political route she is also, might want to exercise, qos, etc. etc. For this reason, the package is basically delivered on the external interface and running through everything, once again, this time as a decrypted packet. If the package hits the ACL twice, once encrypted and clear once.

  Your external ACL shall include the non encrypted and encrypted form of the package.

  Now, if you're afraid that people can then simply spoof packets to come from 10.1.1.0 and they will be allowed through your router, bzzzt, wrong. The first thing that the router checks when it receives a packet on an interface with a card encryption applied is that if the package needs to be encrypted, it is from his crypto ACL and its IP pools. If he receives a decrypted packet when it knows that it must have been encrypted, it will drop the package immediately and a flag a syslog something as "received the decrypted packet when it should have been."

  You can check on the old bug on this here:

  http://www.Cisco.com/cgi-bin/support/Bugtool/onebug.pl?BugID=CSCdz54626&submit=search

  and take note of the section of the security implications, you may need to slightly modify your configuration.

• Cisco 837 and access list

  Hi all

  Sorry if my question sounds stupid, but I had a lot of problems with the syntax of the access list, especially to remove a line in an access list, for example:

  Here is my list of access

  access-list 120 allow ip 192.168.6.0 0.0.0.255 172.16.0.0 0.0.255.255

  access-list 120 allow ip 192.168.6.0 0.0.0.255 172.20.0.0 0.0.255.255

  access-list 120 allow ip 192.168.6.0 0.0.0.255 172.17.0.0 0.0.255.255

  If I want to delete only this line

  access-list 120 allow ip 192.168.6.0 0.0.0.255 172.16.0.0 0.0.255.255

  I do not know how, I if do:

  no access-list 120 allow ip 192.168.6.0 0.0.0.255 172.16.0.0 0.0.255.255

  all the access-list 120 is removed!

  Help, please!

  Olivier

  Hi, this is the usual behavior, if you delete the access list of the entire statement with sequence number is deleted.

  You can create a named extended access-list and have the sequence number for each statements.

  !

  Standard IP access list note

  permit 172.10.0.0 0.0.255.255

  10.1.1.0 permit 0.0.0.255

  permit 192.168.1.0 0.0.0.255

  deny all

  !

  and if you want to delete something in between, or any particular line, you can run the command like this that will remove this line instead of the entire ACL itself...

  Standard note of access-list (config) #ip

  (config-std-nacl) #no 3

  This configuration lines will remove the third line only (which is to allow the 192.168.1.0 0.0.0.255, leaving the other statements)

  regds

• Effect of the access lists on free access of high to low by default

  I'll implement access rules list on PIX525 (V6.3) with several DMZ, but want to minimize the rules.

  Scenario - 3 interfaces (inside (secuity100, average security50 outside Security0)

  To allow hosts on the way to reach the inside I create an access list applied to a central interface. However, will be an implicit (or explicit) deny at the end of the access list prevents the intermediate hosts with default value to open access to the lower security outside the interface?

  Thank you

  Mick

  Level of security and access lists:

  To grant access of lower to higher level, you need to an access list and a static.

  Equal to equal level cannot talk to each other.

  Higher level of security can talk to lower levels, if there is no access on this interface list and the NAT is configured correctly.

  ACL will add at the end a "deny ip any any" after a statement of license. So getting back to your question: If you allow a DMZ host to connect internal host on a specific port that all other connections are blocked. You must specify all the tarffic in this access list otherwise they will be blocked.

  The only exception is the traffic may be from other interface access lists to the demilitarized zone, answers etc. For example, you are allowing port 80 to a dmz host outside this traffic will not be verified again by the dmz access list.

  sincerely

  Patrick

• ASA - same-security-traffic allowed inter VS permit/deny access-list interface

  Hi people,

  I wonder if I use the same-security-traffic permits inter-interface order to ASA and I have 2 separate interfaces with the same level of security and ACL with a few rules explicit allow , if not covered by these statements to allow traffic will be blocked by implicit deny at the end of the ACL or am I completely wrong in my thinking?

  That is right.

  But then if you have an interface with an ACL and another interface without an ACL and you want to pass traffic between the two interfaces, then the interface without an ACL will rely on the level of security while configured with the ACL interface will rely on configured ACL entries.

  --

  Please do not forget to select a correct answer and rate useful posts

• Public static NAT vs. Access-List

  Hello

  I have a question what is the best practice static NAT and access list. Example:

  Server (192.168.1.1) Web inside to outside (10.10.10.10) with the port 80 and 443.

  IP nat inside source static tcp 192.168.1.1 80 10.10.10.10 80

  IP nat inside source static tcp 192.168.1.1 10.10.10.10 443 443

  Or

  IP nat inside source static 192.168.1.1 10.10.10.10

  Access-list 101 permit tcp any host 10.10.10.10 eq 80

  Access-list 101 permit tcp any host 10.10.10.10 eq 443

  interface ethernet0
  IP access-group 101 in

  Thank you

  The operational reasons - it will break things.

• VPN list and access

  Hello

  I have a router Cisco SOHO 97 and I set up VPN to access through VPN client.

  There is no problem: VPN Client Connection--> OK, access to my network--> OK

  If I activate the IOS with CRTS Firewall: VPN Client Connection--> OK, but I can't access my network.

  This line is added when I activate the firewall:

  inspect the name myfw cuseeme timeout IP 3600

  inspect the IP name myfw ftp queue time 3600

  inspect the name myfw rcmd timeout IP 3600

  inspect the name myfw realaudio timeout IP 3600

  inspect the name myfw smtp timeout IP 3600

  inspect the IP name myfw tftp timeout 30

  inspect the IP name myfw udp timeout 15

  inspect the name myfw timeout tcp IP 3600

  inspect the name myfw timeout h323 IP 3600

  ------

  interface Dialer1

  .....

  IP access-group 111 to

  inspect the myfw over IP

  ...

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

  access-list 111 allow a whole icmp administratively prohibited

  access-list 111 permit icmp any any echo

  access-list 111 permit icmp any any echo response

  access-list 111 permit icmp any a package-too-big

  access-list 111 permit icmp any one time exceed

  access-list 111 allow all unreachable icmp

  access-list 111 permit udp any eq bootps any eq bootpc

  access-list 111 permit udp any eq bootps any eq bootps

  access-list 111 permit udp any eq field all

  access-list 111 allow esp a whole

  access-list 111 permit udp any any eq isakmp

  access-list 111 permit udp any any eq 10000

  access list 111 permit tcp any any eq 1723

  access list 111 permit tcp any any eq 139

  access-list 111 permit udp any any eq netbios-ns

  access-list 111 permit udp any any eq netbios-dgm

  access-list 111 allow accord a

  111 refuse a whole ip access-list

  (1) when I use ip only inspect there is no problem, the VPN connection working well.

  (2) if I use the access list, the network is inaccessible by VPN

  I have enabled ipsec with this list of access permit udp any any eq isakmp

  Access list who should I add?

  Thanks for your help

  You must allow the form encypted traffic (which you did with the ESP and lists access UDP/500) and the unencrypted form of traffic (Yes, really).

  This is because the access list turned twice to the IPsec packets. The arives package in the interface as an IPsec packet, pass the LCD and is decrypted in the router. At this point, the router it back on the incoming interface to be treated accordingly. This means however that the decrypted packet is then run through the ACL check again.

  For VPN clients, add a line to ACL111 that says:

  > allow ip access-list 111

  It is the way that routers have always worked. There was a bug to change this behavior for quite a while now, but unfortunately would require a major change in the way in which the IPSec packets are handled internally in the router, so it's quite a difficult solution. Bug ID is CSCdz54626 (regular incoming ACL is treated twice for IPSec traffic).

  If you fear that it is a security risk, then don't be. If someone spoofs a bunch to look like it came from your VPN address pool, the first thing that would make the router is to recognize that this package have been encrypted. Because it is not, the router will drop the packet immediately.

• Preference system, security and confidentiality, accessibility - not working/empty

  Hello

  All of a sudden my system preference, safety and confidentiality, accessibility access list does not work, it is completely empty/Virgin and I can't use + / either. They do nothing. The + tries to add an app and I can select an app via the dialog box, but the window just shows blank after choosing an app. He never adds anything.

  I reboot several times and turned to cycling as nothing will do. I also zapped the PRAM, still nothing. I also used the Onyx to repair permissions and also checked the disk, everything going perfectly.

  The list never used to be empty, there are several apps listed in there, but they are all gone now. It is completely empty.

  I have problems because the apps that were once, now on the list will not work until I have added to the list, but I can't. I would like to buy yet another application that could control this list, but I don't know of any application that does.

  I hope someone has a solution or an idea of what to do because you have lived the same exact situation.

  I am running 10.11.5

  Thank you

  -Doren

  

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  The title of the Console window should be all Messages. If it isn't, select

  SYSTEM LOG QUERIES ▹ all Messages

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• My computer can not VAT registration and access the internet when connected to the network [secure] through wireless.

  Original title: fix problem 'local only' what is wireless.
   
  -My computer is a HP Pavilion dv5, running windows vista edition Home premium

  -My computer can identify and access the internet when connected to the network through a cable.

  -My computer can identify and access the internet when it is connected to the grace wireless network [without warranty].
  -My computer can't identify [unidentified network] and [room only] internet access when it is connected to the [secure] grace wireless network?
  -Other information systems, identify and access the internet when it is connected to the [secure] grace wireless network.
  -J' confirmed the network, try password works in "safe mode with network", manually configured (TCP/IPv4) using a connected computer.
  S ' Please, I'm desperate and in urgent need of help.

  Hello

  1. If it works well before?

  2 have you made any changes to the computer before the show?

  Method 1:

  You may experience connectivity problems or performance issues when you connect a portable computer that is running Windows Vista or Windows 7 to a wireless access point:
  http://support.Microsoft.com/kb/928152

  Method 2: Uninstall and reinstall the network adapter drivers.

  Follow the steps mentioned.

  (a) click Start, right click on computer.
  (b) click on properties, click on Device Manager
  (c) expand the network card, right-click the wireless adapter option
  (d) click on uninstall
  (e) now go to your computer/wireless device manufacturer's website, download the updated drivers and install them.

  Follow the below mentioned article:
  Updated a hardware driver that is not working properly
  http://Windows.Microsoft.com/en-us/Windows-Vista/update-a-driver-for-hardware-that-isn ' t-work correctly

• Access-list group policy and IPSec tunnel.

  I have an IPSec Site to Site VPN tunnel that ends on the external interface of the firewall. My ftp server is located in a demilitarized zone. The DMZ has an access list applied to the interface. When I created the Group of the tunnel for the Site to Site, I create a group of tunnel with group policy and manage the policy with filters. The filter looks like an access list. Are the filter and the ACL interface work together? The one replace the other? How they work together.

  Once traffic ipsec, acl interface is not used until you have enabled "sysopt conn allowed-/ ipsec vpn. When you add a vpn-filter, it is what will filter the ipsec traffic.

• access list for traffic crossing and IPSEC

  Hi, just a question fast and easy if everything goes well as im on thinking that he. IM on the establishment of the IPSEC between a Cisco router to another Cisco router. I want to only allow RDP through IPSEC.

  I of course implement the ACL for the SHEEP, but I'll have to implement another ACL application outside? interface allowing a specific RDP server and denying everything.

  Thank you

  David

  I have extracted this router to work. I changed some details to conceal the source, but it should illustrate what you need to do.

  !
  crypto ISAKMP policy 1
  BA aes 256
  preshared authentication
  Group 2
  address of examplekey key crypto isakmp 2.3.4.5
  !
  !
  Crypto ipsec transform-set esp - aes 256 esp-sha-hmac AES256SHA
  tunnel mode
  !
  cust_map 10 ipsec-isakmp crypto map
  defined peer 2.3.4.5
  game of transformation-AES256SHA
  match the address crypto_acl
  !
  interface GigabitEthernet8
  cust_map card crypto
  !
  crypto_acl extended IP access list
  host ip 192.168.25.52 permit 172.24.0.0 0.0.7.255
  !

  HTH

  Rick

• Cisco ISE and WLC Access-List Design/scalability

  Hello

  I have a scenario that wireless clients are authenticated by the ISE and different ACL is applied depending on the rules in the ISE. The problem I have seen is due to the limitation on the Cisco WLC that limit only 64 input access list. As the installer has only a few IVR/interfaces and several different access lists are applied to the same base on user groups interface; I was wondering if there may be an evolutionary design / approach according to which the access list entries can evolve next to create a vlan for each group of users and apply the access list on the interface of layer 3 instead? I illustrated the configuration below for reference:

  Group of users 1 - apply ACL 1 - on Vlan 1

  User 2 group - apply ACL 2 - on the Vlan 1

  3 user group - apply ACL 3 - on the Vlan 1

  The problem appears only for wireless users, he does not see on wired users as the ACLs can be applied successfully without restriction as to the switches.

  Any suggestion is appreciated.

  Thank you.

  In fact, you have limitations on the side of the switch as well. Long ACL can deplete resources AAGR of the switch. Take a look at this link:

  http://www.Cisco.com/c/en/us/support/docs/switches/Catalyst-3750-series-switches/68461-high-CPU-utilization-cat3750.html

  The new WLCs based on IOS XE and not the old OS Wireless/Aironet will provide the best experience in these matters.

  Overall, I see three ways to overcome your current number:

  1. reduce the ACL by making them less specific

  2 use L3 interfaces on a switch L3 or FW and the ACL is applied to them

  3. use the SGT/SGA

  I hope this helps!

  Thank you for evaluating useful messages!

• Critical auth and limited access-list

  I play just with ISE 1.1.4 and auth critical, but I have a pretty locked down from the default access on ports list. Is it possible to replace a list of very restrictive access by default in the event of critical auth?

  It seems as if you are relieant on DACLs to provide access for devices (closed or similar mode) auth criticism is not a viable option?

  Or have I misunderstood, and perhaps "action dead event server authentication allows voice" more I waited.

  I guess I'm looking for something like "event action dead access-list less-restrictiveACL server authentication."

  Thank you

  Gas

  Why not flip it on its head and have your less-restrictive-ACL default and impose more restrictive things through dACL?