Archive for the ‘Computer network’ Category

TMG 2010: Site to site clients cannot access TMG server

October 8th, 2012 No comments

When I upgraded from ISA 2006 to TMG 2010 I found some special problem. There was HQ with TMG 2010 and one branch with ASA 5505. Between those two location there was Site to Site VPN tunnel created. Everything worked fine, beside one problem. Users in branch couldn’t access anything on TMG server. They couldn’t ping it or do anything with it. They couldn’t browse Internet, because TMG was also web proxy server for them.

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Upgrade from ISA 2006 to TMG2010

September 25th, 2012 No comments

Customer wanted to upgrade his ISA 2006 server to “new” TMG 2010. I thought it would be nice and easy process. It could be if there were no problems which I didn’t expect to be a problem in “new” software. Old server was still functional and I wanted to prepare new server and migrate all settings and certificates.


To install all requirements you can install required packages by yourself or you can use Run Preparation Tool from installation screen of TMG. Why didn’t they include it into installation package it self?

Messed up console

When I was done with installation I ran TMG console and I received following error:

An error has occured in the script on this page.

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HP-UX problem with disks from SAN

June 14th, 2012 No comments

We had project replacing SAN switches. Customer has one old HP-UX (HP Unix) system. This system is very sensible about SAN changes.

Normal situation

You can see all hardware using command (

ioscan -fnC

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SYSVOL FRS to DFSR migration

April 16th, 2012 1 comment

Most of you probably already updated Active Directory infrastructure from Windows 2003 to Windows 2008 R2. What I see most is that administrators do not upgrade DFS replication subsystem for SYSVOL shares. Before Windows Server 2008 (also R2) was released FRS (File Replication System) is used. In Windows 2008 R2 there is new version released and it’s called DFSR (Distributed File System Replication).


FSR uses NTFS volumes’ USN journal to determine when a change has occured to a file and triggers replication. When FSR detects file close it gathers information about file and it’s attributes. It also checks file’s MD5 hash. If MD5 hash changes it will trigger replication. If file has changed whole file is send to FSR replication partners.


First benefit of DFSR is that it doesn’t replicate whole file, but just a changed data in the file. To be able to check only changes in files it uses RDC (Remote Differential Compression) compression algorithm.

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Windows XP ping (ICMP) payload

October 14th, 2011 No comments

I was wondering what would Windows XP payload to be. I always thought that there will be random characters or something like that, but I was wrong.

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CCDP Certified

May 17th, 2011 No comments

Hello all

Today I earned another Cisco certificate.

Categories: Computer network, Unassigned Tags:

Spanning Tree Protocol on HP Procurve switches

April 5th, 2011 1 comment

I played with HP Procurve switches and I found one weird default setting. Spanning Tree Protocol is disabled by default. It was weird finding because I tried to interconnect two switches with pair of cables whole my network went down 🙂 It was overloaded with b-cast storm.

Windows 2008 network performance problem

March 26th, 2011 No comments

Today I was facing weird problem at our customer. They have IBM HS21 blade server with build-in dual-port Broadcom network card. There was only Windows 2008 installed with all up2date drivers. Everything worked fine besides network performance. Upload from server to other servers was around 20MBps, which is fine. Problem was download to server, because it was 1-2MBps.

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Čas v doméne

April 22nd, 2009 2 comments

Veľa krát sa stretávam u zákazníkov s tým, že ľudia sa sťažujú na rôzne posuny časov tak na ich klientských počítačoch ako aj na serveroch. Read more…

Záloha DHCP servera na sieti

April 21st, 2009 No comments

V poslednej dobe sa hovorí čo raz viac o Disaster Recovery plánoch. Sú to predpripravené scenáre ak sa niečo stane v budúcnosti. Napríklad požiar v hlavnom dátovom centre a pod.

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