CentOS 5 Networking :: RDNS For E-mail Server Configuration - NAT Involved?
Aug 24, 2009
I'm having an issue with an e-mail server (with an IP of 10.10.0.1) which is behind NAT (Cisco ASA) which in turn of course has it's own external IP (let's say - IP 10.10.0.100). Both IPs are public.Now, if i wanted to set up a correct RDNS configuration for my domain, what should be the IP address entry for the PTR record in this case?
I know this is strictly network configuration related question (not Linux, or CentOS for that matter), but I wouldn't be asking if I didn't get a few bouncing e-mails every once in a while (i.e. NDRs) with messages like: You do not have permission to send to this recipient. For assistance, contact your system administrator.
There is an requirement, intranet people they may not have internet access but they want to send mail to external domain(internet),but in that intranet network one machine can have internet access. Is there any solution for this requirement.
I use the DynDNS service to keep track of my home server IP. The problem here is that when I try to access my web server via my domain name, the connection is refused. If I first obtain the ip adress (via nslookup), I can get access. I checked the reverse dns lookup and the results dont match. Perhaps this can be a problem browsing. Does the browser or the OS perform the rdns check? Is there a way to whitelist some specific domain in order to skip that check, so I dont have to find out the IP address every time i want to access my home server.
I've setup my server by following a ton of goods, and it seems to work ok, but I need to start using my server for email in order to receive orders placed via my website. I've followed this guide - [URL] I followed the steps above, and tested the mail server via telnet, and all seemed to be ok. I tried sending an email via Squirrelmail, from cs@thinclientwarehouse.co.uk TO my working email simon@c1systems.co.uk, but the server returned with the following message:
<simon@c1systems.co.uk>: host mail.c1systems.co.uk[95.128.128.129] said: 550-Verification failed for <cs@localhost.thinclientwarehouse.co.uk> 550-The mail server could not deliver mail to cs@localhost.thinclientwarehouse.co.uk. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries. 550 Sender verify failed (in reply to RCPT TO command)
I am setting up a CentOS box as a NAT firewall that needs to also send mail. It needs to send this mail using an outside provider's SMTP. The provider requires SMTP over SSL. None of the machines inside the NAT will ever send mail except via the provider's SMTP nor will they ever receive mail except to local clients via the provider's IMAP servers.
So for the example the machine is TESTMACHINE. There is one internet facing ethernet port connected to a DSL modem via pppoe.
The SMTP it needs to send mail via is mail.host.net which requires SMTP over SSL (port 465) and username/password authentication.
The sendmail documentation is quite confusing on how to get this simple setup operating, so an example showing the appropriate changes to sendmail.mc and other require config files.
I have to administer a few mail servers, a mail log server, 4 nameservers and a web server -all running on Centos 5 server distributions. Now I have a task: to avoid accidental crashes on the production servers while installing updates, my boss asked me to do clones (these clones will all be VMware virtual machines) of the servers (EXCLUDING the actual e-mails and mail log contents) and then to run those clones on VMWare Server. This way, first I will install and test updates on the clones and - if they will be running without crashes - I will apply the updates on the real production servers themselves. I have already installed VMWare Server 2.0 I have a few questions:
- How do I build the virtual machines to exclude the actual mail files and mail logs? Can I use VMware Converter for this purpose, or do I have to use another program? - How do I actually do this cloning? Is there a tutorial on how to do this?
i'm trying to send a mail with "mail" on my cent os console , but without success. In Suse it's quite simple with "mail": mail -r sendersaddress@domain -s "subject" targetaddress@domain </tmp/filewithcontent
I will be relocating to a permanent residence sometime in the next year or two. I've recently begun thinking about the best way to implement a home-based network. It occurred to me that the most elegant solution might be the use of VM technology to eliminate as much hardware and wiring as possible.My thinking is this: Install a multi-core system and configure it to run several VMs, one each for a firewall, a caching proxy server, a mail server, a web server. Additionally, I would like to run 2-4 VMs as remote (RDP)workstations, using diskless workstations to boot the VMs over powerline ethernet.The latest powerline technology (available later this year) will allow multiple devices on a residential circuit operating at near gigabit speed, just like legacy wired networks.
In theory, the above would allow me to consolidate everything but the disklessworkstations on a single server and eliminate all wired (and wireless) connections except the broadband connection to the Internet and the cabling to the nearest power outlets. It appears technically possible, but I'm not sure about the various virtual connections among VMs. In theory, each VM should be able to communicate with the other as if it was on the same network via the server data bus, but what about setting up firewall zones? Any internal I/O bandwidth bottlenecks? Any other potential "gotchas", caveats, issues? (Other than the obvious requirement of having enough CPU and RAM).Any thoughts or observations welcome, especially if they are from real world experience in a VM environment. BTW--in case you're wondering why I'm posting here, it's because I run Debian on all my workstations/servers (running VirtualBox as a VM for Windows XP on one workstation).
i have an server which have my site on it, server have an public ip and site works fine..the thing that i done to enable mail server is :
1.select sendmail option as mail server(in joomla). 2.install and configure sendmail in server (which ubuntu installed on it )
**if i use my website locally mail server works fine i can send message and receive , but when i use web site from Internet mail server seems not working at all
I am hoping to find some much needed help here. I have been to various other sites and am beginning to think that I am not meant to have a server of my own.
I was told that OpenSuSE was good for beginners. So far, I am wondering.I am trying to set up a home network ( 2 laptops, 1 desktop. The laptops are wireless )
I'd like to set up a web server to run a personal webpage or two and maybe a forum, shoutcast server and IRC at some point down the road after I figure out the first two.
I found a guide, but it was for 64 bit and wanted me to install ISPConfig 3 ( Which, obviously I don't need )
I would like some basic, beginner help on installation, configuration and whatnot on setting up a web-server and mail server.
Yes. I have a static IP ( leasing an IP block from my ISP ). Yes, they allow me a web-server and mail server ( I had to get the IP block to do so ) and I have my own domain name to use.
On the various attempts, I managed to get apache working. ( When I visit my domain name, it says "IT WORKS!" which is nice and all, but I am use to using Cpanel and have no clue how to setup / edit a website outside of a panel ( or even FTP )
I think I got the mail server installed, but again ( as with the web server ) have no clue how to setup / configure and use it.
I either am using the wrong search words for help or asking incorrectly or something. This is my final stop. I am at the point of just forgetting it, chalking it up to a lost cause.
I do hope someone here is willing to be patient with me and help me through it all. I will even give link backs and Kudos to this site if it all works out.
i want to authenticate user (client) via switch to the radius server(CentOS)Can anyone tell me the authentication/authorization configuration that should be made in the switch (huawei) and the radius server(centos).Esp. the main files under /etc/raddb/ in the Server& the configuration to be made under the radius server template "test"( as of my case)...
I have a few mail servers, a mail log server and a web server running on Centos 5. Now I have a task: to avoid accidental crashes on the production servers while installing updates, my boss asked me to do clones (these clones will all be VMware virtual machines) of the servers (EXCLUDING the actual e-mails and log contents) and then to run those clones on VMWare Server. This way, first I will install and test updates on the clones and - if they will be running without crashes - I will apply the updates on the real production servers themselves.
I have already installed VMWare Server 2.0 I have a few questions: How do I build the virtual machines to exclude the actual mail files and mail logs? Can I use VMware Converter for this purpose, or do I have to use another program? How do I actually do this cloning? Is there a tutorial on how to do this?
I would like to run a mailing daemon on my system that would receive incoming mail and forwards it to my Gmail account. I have no experience in mail services and forwarding mail at all. where to start reading and/or look for clues?
i need to install a mail server with the following requirements: smtp, imap, web administration interface (users management to be done by a non-specialist) and ... to be easy enough to install/implement on debian (this is one time deal for me ...)
i used until now Xmail, phpxmail and nocc, very easy to install and it was working flawlessly, but unfortunately nocc is a too poor webmail client be cause is based only on pop3 literally the requirement is that on the web[client] mails sent must be saved and from what i see on webmail that only can be done with imap and (this is the big problem) Xmail does not support imap so i cannot install a good webmail client
I am ashamed that I am causing other people troubles, but apparantly my server is involved in attacking the servers of other people.
I have to admit that I am not too familiar with using a CLI, or Linux for that matter, but I have a Debian server running under Plesk 10, which is colocated.
Now I have received messages from the datacenterm which state that my server is involved in brute force attacks.
The messages show a lot of lines like this:
Code:
The only I get from my hoster is to back up all domains and re-install the machine.
I want to resolve this asap, but do not agree with that action for two reasons: the machine just had a fresh re-install 2 months ago, so if it is a flaw in the OS, I will get the same flaw back, and if it is not OS related but due to a domain, I will get the problem back by putting back the backed-up domains.
But now I'm stuck: what steps should I follow to try and find the cause of this evil and make sure that my machine will not bother other machines anymore?
I realize that this probably will be a steep learning-curve, but please bare with me and help me to resolve this.
What have I done so far?
1) There are a number of live sites on this server, either running WordPress or Joomla, I have made sure they are all updated to the latest release.
2) I have manually looked at the source code of the index-files of those sites, haven't seen anything strange, like redirects.
3) I have used online scanners to check all sites for malware, all have been reported back to be clean.
4) I have run the Plesk-version of RKhunter, and that gives me certain warnings which I cannot (or do not) understand:
Code:
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I received the first report of these attempts about a week ago and immediately changed the Plesk/SSH password to a 200bit password generated with KeePass, hoping that would keep out any evildoers.
I would like to discuss setting up a mail server and its implications and alternatives. First, let us see if I have understood this correctly: A mail server consists of many different components. First, a server to listen to any mail inbound for a specific domain (say postfix), and then a POP3/IMAP server (say dovecot). Then, I should somehow configure the rules by which all mail is forwarded to their respective owners. This should be fairly simple by using debians package managers and dselect or whatever program it is that sets up right packages by use cases at the install.
But now lets assume a more complicated environment, where there are multiple users with different domains and needs. First, we need to send mail to ourselves from webapps for instance for backup purposes. So let's say we have a domain called domain.com setup, and we want to send mail to backup@domain.com. Unfortunately, some configuration issue makes the application get confused, because it is trying to send mail to itself, but doesn't quite understand what it should do. How can this problem can be solved?
Second, how could I configure different domains with different rules. For instance, if I want one domain to have a catch-all account, where random email sent to erroneous accounts is captured? Or if I want to create accounts which are not based on actual Debian accounts, but instead just random usernames (say, danny@domain.com, mike@domain.com, support@domain.com etc.)?
Finally, which are the best web-guis for doing such configuration? What if the customer wants to himself add accounts? I cannot require him to edit text files - especially if he can thus break the whole configuration for other customers as well.. postfix-admin is one, but it is quite crude-looking. Is there something which integrates both postfix, apache and dovecot configuration? How about Webmin?
Being a New user of Red Hat Ent. Linux 5.1, I need Step by step configuration documents of FTP/DNS/MAIL/Appache/SAMBA individually and individual Test of each configuration after configuration. I had gone thru' RHEL Documents but there is no step by step configuration
I'm trying to do some network bonding in RHEL 5.4, and I'm not seeing the results I expect. I have set up a number of servers using mode 1 with no issue, but I need to configure a new server differently. bond1 is created from eth1 & eth2 bonded together using mode 802.3ad with layer2 lacp bond0 is created from bond1 & eth3 using mode active-backup with bond1 as the primary interface When I bring the network services up, all traffic is passing over eth3 instead of bond1, which is the primary. Below are the modprobe.conf * ifcfg-* files involved.
My modprobe.conf: alias eth0 e1000 alias eth1 e1000 alias eth2 e1000 alias eth3 e1000 alias scsi_hostadapter mptbase alias scsi_hostadapter1 mptsas alias scsi_hostadapter2 qla2xxx [Code].....
Could anyone point me to some simple articles that explain what email encryption is and how to set up a mail server (e.g. Exim) that can send secure emails? I know nothing about networks, mail servers, encryption, etc., but I have to be an expert on it before I walk into work tomorrow morning.
I was wondering if there was some kind of anti-spam proxy available for debian, that could serve as a layer between my ISP's mailserver and my email client. Something light, as it needs to be installed to a guruplug server with not much storage available. It would be great if I don't need to configure a fully fledged mail server but if it can function on it's own, only filtering spam messages. I already found assp and qpsmtp, but I find these very difficult to setup and assp is like huge.
I have an OpenSuse 11.2 system that is running 2 BBS systems independently, both of which are capable of receiving smtp mail on prot 25. What I would like to do is set up Postfix on the OpenSuse OS to receive all mail for both those domains and then send the relevant mail to the correct BBS. I would therefore have Postfix listening on Port 25 External and the 2 BBS applications listening on different ports on the localhost address. At least that is the plan.
how to do this. I want to do it and still make sure Postfix is secure and not accidentally open up any nasty relay holes etc etc.
I have one server at home, connected through a router that gives me a static IP:192.168.1.2 - My PC192.168.1.3 - CentOS serverI enabled the port 80 into router forwarding system and I can connect properly to CentOS server, using the IP my internet provider gives me. My router automatically forwards a changed IP to my dyndns.com account so I can also access the server through a domain name (I pay to have it linked to one of my domains).My next step is to configure the mail server (dovecot) , so I can send emails from my local server(192.168.1.3).I was wondering if anyone has any tutorial links or tips to have the mail server configured through a home internet provider + home router.
Could it be the IMAP file is corrupt?I have set up mail server on Centos to receive via dovecot.One of my user accounts (A single account out of a hundred)cannot receive their mails.
I am running a CentOS 5.6 Server with a website and Forum. The website has a contact form and users can email various people in the organization. I have setup sendmail to send any mails like this to my email address on a Windows machine.The problem is that there emails don't have a header which has the senders original email header. It comes from localhost on my sendmail. How can I get any mail generated from the apache site to ALSO send mail to root on the Centos Server? That way I should be able to see the header and report the spammer or block them.
I followed the Wiki guide for configuring my Postfix server for SASL / TLS. I don't get any errors and I assume it's working but when I try and test SASL (saslauthd), I don't get the response noted according to the Wiki and I don't understand why.
i have successfully done the setup of postfix and dovecot on this link [URL]I run Cent OS on top of window 7 via VM Player,i want to access mailbox from windows 7 using email client like Thunderbird and Outlook. What setting i need to do in my mail server ?
