Goline Logo


  • Route RPKI validation April 1st, 2022
    RPKI is a security framework by which network owners can validate and secure the critical route updates or Border Gateway Protocol (BGP) announcements between public Internet networks. BGP is essentially the central nervous system of the Internet and one of its fundamental building blocks. The main function of BGP is to facilitate efficient routing between Autonomous Systems (AS), by building and maintaining the Internet routing table. The Internet routing table is effectively the navigation system of the Internet and without it, traffic would be unable to flow between its constituent networks. Unfortunately, routing equipment alone cannot distinguish between legitimate and malicious routing announcements,...
  • RIPE – Atlas Anchor February 17th, 2022
    We have become an even more integral part of the RIPE Atlas project by hosting an anchor, a device that allows for latency analysis of traffic between autonomous systems.https://atlas.ripe.net/probes/7073/RIPE Atlas anchors play an integral role in the RIPE Atlas network by acting both as enhanced RIPE Atlas probes with more measurement capacity, as well as regional measurement targets within the greater RIPE Atlas network. Anchors are able to perform many more measurements than a regular RIPE Atlas probe, and the large amount of data they collect is made available to everyone. In addition, anchors act as powerful targets that can...
  • MANRS June 20th, 2020
    GOLINE firmly believes in initiatives to protect networks, improve security and resilience of the global routing system. Therefore we decided to support the MANRS project and join as participants.Mutually Agreed Norms for Routing Security (MANRS) is a global initiative, supported by the Internet Society, that provides crucial fixes to reduce the most common routing threats. MANRS offers specific actions via four programs for Network Operators, Internet Exchange Points, CDN and Cloud Providers, and Equipment Vendors. Requirements for Participation Please read the full MANRS Actions document before applying. You can become a participant if you meet these requirements: You (or your company) support...

Cisco ASA: web interface not working

Paolo Caparrelli Cisco ASA 22 June 2022

Cisco ASA: web interface not working

I had to troubleshoot a Cisco ASA today, where the client wasn’t able to connect to the management web interface anymore via https. The customer didn’t install ASDM locally, but always starts the Java-based version.

After upgrading the Cisco ASA to software version 8.2(1) and a reboot, the client wasn’t able to connect to the web interface anymore. I was able to connect to the firewall with my locally installed ASDM client, but I couldn’t access the web interface either.

While troubleshooting I first tried the basic settings, like management access-list, regenerate crypto keys and change the management port. All these options didn’t help, but the strange thing was that the web interface was working remotely.

While working with Mozilla I received the following error:

cannot communicate securely with peer: no common encryption algorithm(s).

In Google Chrome I receive the following error:

Error 113 (net::ERR_SSL_VERSION_OR_CIPHER_MISMATCH): Unknown error.

And of course Internet Explorer didn’t gave any usable information. I started looking at the supported encryption algorithms within the firewall with a show version. I noticed that VPN-3DES-AES was disabled. The next step was the enable the VPN-3DES-AES ciphers. The upgrade license for this feature is available for free at http://www.cisco.com/go/license.

I activated the VPN-3DES-AES feature, but still wasn’t able to connect to the firewall with the web interface. I checked the SSL encryption used by the firewall.

fw01# show ssl
Accept connections using SSLv2, SSLv3 or TLSv1 and negotiate to SSLv3 or TLSv1
Start connections using SSLv3 and negotiate to SSLv3 or TLSv1
Enabled cipher order: des-sha1
Disabled ciphers: 3des-sha1 rc4-md5 rc4-sha1 aes128-sha1 aes256-sha1 null-sha1
No SSL trust-points configured
Certificate authentication is not enabled

The firewall still didn’t enable the ciphers supported in my browser. If the VPN-3DES-AES license isn’t installed, only the cipher des-sha1 is enabled by default. I added the correct ciphers with the following command:

fw01(config)# ssl encryption aes256-sha1 aes128-sha1 3des-sha1

After adding the command I was able to connect to the ASA with both the web interface and the ASDM.

0 0 votes
Article Rating
Notify of
Inline Feedbacks
View all comments
Would love your thoughts, please comment.x